I guess the two questions to ask concern desired portability and capacity. I stepped up initially from the Ridgid to the Midi, but then returned the Midi within the 30 day time period to get the CT26. Nothing wrong with the Midi (all Festool vacs have the same power), but I just felt that with a lot of routing and TS work, the extra capacity on the 26 was worth it. I know sometimes people favor portability if they're doing a lot of moving around on a job, and therefore prefer the smaller size of the Midi. To be honest, the CT26 is not that heavy even when the bag is full -- but then again, I don't do work where I'm constantly walking up and down stairs, and so maybe would feel differently if I were. I suspect, though, that many who prefer the Midi for site work have a larger model as their stationary vac. In terms of system integration, both the Midi and the 26 have sys-docking at top.