Went from an older iPhone to the Atrix, with a ~10 day pit stop on the Inspire inbetween.
Battery life was probably my biggest complaint with the Inspire, followed by the fact Sense felt... really clunky to me, I guess. It's pretty, I guess, if you're into the full page widgets. I guess my biggest frustration was wanting it to work kind of like iOS works; if I wanted to move a widget or shortcut I had to move what was there to another screen, move the new widget into place, and then move the old widget back. Drove me nuts.
blur could do some things a bit better, and it is slightly laggy, but I expect things will improve as Android updates come out. The touch screen is a little bit 'loose', but I got used to it pretty quickly. Moto keyboard is kind of meh, but I absolutely love the Swype keyboard, both for typing and swiping. I think I like the Atrix screen better, pentile and all, but the Inspire screen was pretty nice as well.
I do kind of miss the Inspire camera, but I was starting to kind of hate the phone the more time I spent with it. The Atrix is the opposite for me... I brushed it off as being way too gimmicky with docks and all initially; I was skeptical that it would actually be a good phone. Now I'm absolutely loving it.