Hi Dave,
Not sure whether you have already decided on a vac but I use a midi with a 1010 router, TS55 and DTS400. All work very well. Of course, with some jobs no vac is going to get all the dust, but mostly it is very good.
Recently I got the CS50 Precisio table saw, which I believe is not available in the USA (and it is a fantastic machine, so start nagging Festool usa). This comes with 50mm hose which does not go into the midi. I asked Festool about this and they told me the midi and mini where specifically designed for painters (i.e sanding) and not for sawing. However, he did advise me to get some 50mm PVC piping and use that between the vac inlet and the hose. Brillant! The 27 mm hose that I initially used between the saw and the vac just had too much resistence. Now, with the 50mm hose and PVC, almost all the dust gets sucked into the midi. Only special cuts leave some dust.
However, the midi does have a rather small container when you do alot of sawing. If you only plan to do occasional sawing, you could go for the midi. If you expect or plan to do more, go for the 22 (or new 26) model.
Cheers
Mattijs