I just this month switched from blackberry to a 700p. I wanted the palm os, and I believe the p has a higher resolution than the w as well.
I have to say, for my purposes, the treo kills my BB 7100. With the palm os there are tons of free programs to make it do whatever you want. I have several video game emulators and several hundred NES, genesis, and SNES games on it (card actually), a couple movies, a few episodes of mr show, the series 3 south, and a bunch of other videos. The evdo is fantastic and streaming media is great. Everything I can think of to make it do someone has written a program that does it. I'm keeping my blackberry for travel overseas since its unlocked, but while the 8700 was tempting, I think I'm keeping the treo for a bit. The screen is not as nice as my sharp 903sh, and the camera is of course not even close to being in the same class as the sharps, but it's adequate.
I can't comment on business uses since I don't have any business to do. Other than having gmail push farealert to my phone. That way at least I know immediately what i missed out on.
I do miss the scroll wheel, but not the freezups when recieving a call while browsing. Touchscreen is convenient and cool. I like the palm desktop software better. I dislike the giant usb connection of the treo. I do like the BB regular usb plug. The blackberry led flashes when in service, which i like so I can find it in the dark, the treo flases when not in service (i think this is different for the 650). With a seidio clear case on the treo is as pocketable as my bb with a vaja case. Moreso actually, since there's less friction. BB was easy to handle without looking at the screen. I knew how to change profiles and etc blind. But the treo has the sound/no sound switch on top, so, draw.
Maybe not helpful observations, but it's all I've got.