Hello! I'm a complete newbe. I googled sandpaper a few days ago and found out there is something called orbital sanders. Now two days later and tons of research I find that there is no clear answer. I am going to start renovating furniture, tables, sideboards, dressers and so on. To start out with, I'm getting 1 sander to do it all. I know this has been discussed a million times but it all comes down to you what you are working on. Terms like smaller/bigger areas is used. But that is all relative, I have no idea if what I'm supposed to do is smaller or bigger areas. I want to use it for stripping old surfaces but above all, get that great finish.

I might get another one further down the road but for now, I can only afford one.

From days of research I found that the Rotex 150 is to heavy but great at stripping, maybe not the perfect finish that I'm looking for.

The ETS 150/5 is not as good at stripping as the Rotex but gives about the same finish.

The ETS 150/3 gives great finish but maybe to weak to do any stripping at all?

Then all of a sudden ETS 125 pops up, this can steal another 2 days from me.

Now they say if you work on bigger surfaces the 150 is better then 125. But what is a bigger surface? Is that a table? Is that a wooden deck in your back yard?

Please help, Im almost out of energy even before I started 

Remember the not so hidden cost of sanding but sometimes over looked. The abrasives the pads the bonnets sponges polishes etc. after the cost of the sander you have a lot of consumables to get initially to do what you want to do.

I bought an RO90 a little over a month ago. It is a great tool but it has a learning curve. I found I was fighting it until I came to grips with the Rotex mode. I started thinking of it more like an angle grinder and learned the muscle memory to keeping it flat, then it was a breeze to use. In fact I like sanding and when I worked out the handling of this tool I had two marathon sanding days with it. Wound up straining my wrist and didn’t pick it up again for over a week. But again I reiterate start thinking of your consumables because I easily have half as much money into new abrasives and pads and still do not have all I would like. But I did like it so much I also have an RO 150 on order, back order. And already have just under 200$ into abrasive and I haven’t even paid for or received that tool yet. So if you haven’t look at your consumable costs now before they sneak up in you!

When reading up on the RO90 it definitely seems to be a do it all machine. I guess 90 is the size of the paper, seems to be really small compared to the others? Maybe that will be a problem?

Yes, the small size is a problem. From a previous owner of the RO90: it is most certainly not a do it all machine because it is too small. I consider it a sander to have on the side, not as a main sander, because it is actually very limited in its usefulness. It is also a costly sander to operate because size for size its paper cost double that of any other sander. And you don't want to put the RO90 on your table top, you'll turn that nice flat frozen lake into a first class ski resort.

and the RO 90 might be the best tool to start with. It might also be that the finish is better using the RO 90 then the RO 150?

No, it is actually the worst tool to start with.

For furniture, a DTS 400 or ETS 125 are the best to start with, and it is best to not want one single sander to do it all, but get a few, like these two. No Rotex is needed for furniture.

Thanks a lot everyone and your post makes alot of sense.

I'm close to deciding now, I'm now convinced the best one is the ETS 125/3. But now I find out that the 125/3 is a lot more expensive then 150/3, I thought it was the other way around. Does the 125 justify the price? From my research and location its about 40% more.

If you are set on Festool, I agree the 125 is a great choice. I own several Festool sanders including the 125 and the 90. The 90 is a good choice for small areas. The problem with a smallish sander pad is that it is too easy to dig into the wood rather than getting a smooth surface. Even a very small “dish mark” shows up like a beacon when you apply a finish. 

I’m currently building a coffee table out of black walnut. The process has been to work through sanding grits from 80 to 180. Dampen the surface to raise the fibers. Sand with 180. Apply finish and sand with 320. I’ll do this 5 times, but not sand after last coat. The table is 35” by 35”.  Using a 125.
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@Zulan I ordered the ro150 because I am doing more floor work and starting to build some tables with ruff stock. My first was the ro90 and as you can see many will tell you it is a specific tool only for certain things. On floors I haven’t had issue with the edges digging in yes I spent and entire day doing a floor with it, my floor, and at first it did dig in, bounce around, and generally make begin to regret buying it. But I spent that time rethinking my approach and after a couple hours it became more fun to use the odd behavior slowly went away. It is a beast to learn to handle. I have not sanded anything last 80 grit yet so I can’t claim it will do a great at fine finishes but I suspect it will do a fine job. We will see once I get my hands on some cherry I’ll be making myself a new dining table and finishing it with the two Rotex. But now that I have easily put 40 hours into the ro90 I love it, but if ease of use and a quick start are important to you it may not be a great first sander. I’m well into my 50’s and have a fair amount of experience with angle grinders and big buffers so I think that helped my learning curve. This isn’t a sander you just grab and instantly make good use of. You absolutely have to learn it. And as I have said before abrasives are expensive! For it and the 150. So far aI have only used granat and it has been the best sand paper/abrasive I have used. I really like it. If you are really wanting to do furniture I would suggest some good scrappers and learning how to use them, a good vac I have the ct26, pay attention to the other suggestions these guys have used way more Festool sander than I have. Also see if you can find a professional furniture restorer and get some first hand advice and see what tools they use provided they are willing to show you. I have gotten a lot of mileage out of good scrapers.

One question are you planning to strip furniture without using strippers? The chemical type not the dancers as fun as that may be. If you are going to chemical strip it will change how you approach refinishing a bit. I mean most tight spots I would sand and scrap by hand so how important would a delta sander really be? 1/4 or 1/2 sheet may be better. Would that be the DTS mentioned above?

I suggest NOT using steel wool. The fibers can get embedded in the wood and, over time, stain the wood if they contact moisture. I use either bronze wool or the white Scotchpad.

Not knowing exactly what your definition of striping is...a few thin layers of shellac or poly clear coat or multiple thick layers of paint?

I was striping a picnic table recently that had multiple layers of paint with a Rotex 125...it was very slow so I grabbed the RAS 115 and the task immediately became easier.

You could purchase both a DTS 400 & an ETS 125 for less than the price of a Rotex 125 and I guarantee they will serve you better than a stand-alone Rotex.

Just yesterday I used a DTSC 400 and an ETSC 125 to sand down some teak outdoor chairs. That DTS/ETS combination is hard to beat.

Not sure what renovation means? I would look at the Porter Cable Restorer or  Makita 9741 wheel sander. Woodcraft sells it, but I didn’t see the PC on Amazon? If your trying to resurface the wood I would go with the PC, if you have a more industrial project like rejuvenating reclaimed lumber go with the Makita. I would get yourself some dust extraction, Festool CT-15? And any FT sander(s) depending on budget and size volume. It’s like asking what flavor ice cream someone likes? eventually you’ll have several sanders,if you stick with it. I didn’t read all the suggestions above, but you would be warranted to read what people gravitate toward and for what reason.

I'm from the UK, so to me "renovation" is not the the same as "restoration".
Not much experience of renovation, but huge experience of restoration.
In my experience the only way and best way to restore anything is to be sympathetic to the  manor that it was made in the first place. Also during the process of restoration, little is more. In other words, going "overboard" is not a restoration at all, it's destructive and devalues the original work you are trying to bring back to life. There is no point in using anything that destroys the underlying charm and authenticity of an object.................just to get it looking new. Why bother....................just make it from scratch and keep the original.

Sanding isn't the primary way to do "stripping" of old finish. A chemical stripper is always the best bet as sanding can very often damage furniture in ways that are hard to recover from, especially with a lot of use of veneer over both solid wood and composite substrates. Any of the sanders you mention can be helpful with the overall process, of course.

For what is worth, I attempted to use a EC125 to strip yeas of Pledge and thick gooey stain from a coffee table. Took forever as the paper was gumming up. Probably should have done a stripper, then lightly sanded.
I almost bought the RO90, but be aware that tool accessories costs will stack up more than the tool costs.  However,  super versitible device. It has the triangle attachment that uses festool sized paper which would have been handy for the corners. Also, it can be a polisher.  The tool is not well balanced, so using it for a long time would not be fun and rocking could cause swirling. To Rotex could also ear vener before you know it.  I still have it on the radar. EC125 did well enough.

The other thing about furniture is to be sure the details and edges are not changed by the tool. The RTS with a extra soft thick pad would be good option, but not for the edges.

I think you will see a lot of furniture flipper youtubers using the Surfprep. I am guessing they give that tool to anyone that has a youtube channel. Their kits are more expensive than the RTS, but come with assorted paper/pads. It is similar to the RTS.  Hartville has the thick pads in stock for thr RTS.

Sanding isn't the primary way to do "stripping" of old finish. A chemical stripper is always the best bet as sanding can very often damage furniture in ways that are hard to recover from, especially with a lot of use of veneer over both solid wood and composite substrates. Any of the sanders you mention can be helpful with the overall process, of course.

To me a stripper is not a "renovation/restoration" tool. At best it can be a "repair" tool for specific parts. But mostly a recycling/re-manufacturing tool. Too destructive to use for anything worth -renovating-. IMO.

I'm from the UK, so to me "renovation" is not the the same as "restoration".
Not much experience of renovation, but huge experience of restoration.
In my experience the only way and best way to restore anything is to be sympathetic to the  manor that it was made in the first place. Also during the process of restoration, little is more. In other words, going "overboard" is not a restoration at all, it's destructive and devalues the original work you are trying to bring back to life. There is no point in using anything that destroys the underlying charm and authenticity of an object.................just to get it looking new. Why bother....................just make it from scratch and keep the original.

Perfectly put @kitfit1. I'm also in complete agreement with @derekcohen. Taking a sander to the canvas of the Mona Lisa won't ever improve it - it'll just destroy it. My advice to the OP would be to tread very carefully before stripping away the entire history of something. If you want new & shiny, go to IKEA.