I too globally hate this new gen 3 system. especially the handles, because they are positioned at the bottom, which makes them useless for carrying the taller systainer, and on the smallest size they cannot be fixed-clicked when stapled... And they are not compatible with the first generation. I still use some of the first generation because I find them more sturdy, so better for very heavy content, and I will put them at the bottom of a staple. I can still put a generation 2 between a gen 1 and a gen 3 for connection, but this is a shame.
Also I loved the generation 2 roll sys (small wheeled tray). The new one (gen 3) which displaced the gen 2 is larger, wasting more space when aggregating several rolling stacks.
There are still some positive things : the XXL systainer is a nice addition for big things, and does not have the bottom handle, although it belongs to the systainer3 (gen 3) serie.
There seem to be some shortage of separately available systainers in Europe, re. the models with the standard width. I suspect this may be related to the Covid pandemic. Systainers are used for storing and transporting the covid tests, which should have resulted in a huge demand. I wonder whether some companies might use those with the black insulating foam inside for the Covid vaccines