I have the M18 vacuum that I bought for a specific project involving removing the concrete dust from holes, it was perfect for that and allowed us to do everything without AC power. I don't know how long it would last if I just let it run, but it can take a pretty big battery, and I don't use it continuously. I have found it very handy for many small clean-up tasks, even though it has a very short hose that doesn't connect to anything but the two small attachements provided. Of course it doesn't stack with other systainers either, so not as handy to bring especailly on a Sys-Roll.
The CTC is obviously much more expensive, with a longer hose, more attachments, probably more power and other features. It looks lke there is a "Plus" version with two batteries and the dual charger coming later, so I will stick with the M18 for now but might get the CTC Plus when it becomes available.