I got one of those 7200 usb boards. It's not the worst one I've used, but it doesn't respond sometimes when something is crashing in an app or OS. I ended up having to shut down via the button and restart. Is that cuz it's usb not PS/2? If it weren't for that I might give it a longer audition time to see what it does for me. I do like the trackball, but the positioning makes me hit the spacebar in attempting to click, so I am not optimistic about it becoming a fave of mine anyway. Before I pick favorites, though I still need to test drive the cherry blues -which I've never sampled- vs the white Alps on the Focus 3001 I just got. ( I like the way it feels, but don't know if it works yet. It seems well used but it does have more snap to it than the new 7200 by comparison even so, and I think I might just like it more than my M- more info to come on this as I test it.)
I think the thumb manipulation of the trackball is awkward enough to keep me from being overly concerned about the switches since I prefer the M5-1 positioning and button application. The 7200 is a little bit counter-intuitive for me and I get more typos than with my Model M or the Dell AT101W but it still better than the microsoft wireless keyboard I used pre-Geekhack.