I had been using the blackberry bold since it's release a bit under 2years ago. The text communications handling within the BB OS feels much more unified in that I had the option of viewing each account and communication program separately or collared together. I haven't found any way to view my gmail and exchange accounts together yet. GoogleTalk is also separate. Nothing huge...just a minor annoyance for me.
Everything else, I've enjoyed thus far. Large screen, snappy processor, pretty good keyboard, solid web browser, etc. While not a complete replacement, the Evo for my needs is coming pretty close to replacing one of my computers. BB excels at being a communications center. The Evo is much closer to a PC. The loss of the spartaness from the BB will take me some time to get used to, but I quite like the UI.
BTW, I wrote this from the Evo while relaxing in bed. Not something I could have done on the BB bold 9000 at the very least...going to miss the ability to use a single phone for both US and Japan, but the pros of this platform/phone far outweigh any problems this exBB user has found thus far.