Both have GPS and overall features. Both are tiny (BB has a kwertylike keyboard), Moto has a slidy thing to the numberpad (I liked the feature in the sony i had). BB is slightly smaller than Moto, meaning Moto has slightly bigger (and better) display.
It seems that Moto has a few more features (nothing I care much about, the 3G and something else), and has had pretty good reviews. BB is relatively new, and has no reviews. The lack of reviews makes it difficult to make an informed decision.
The AT&T Tilt seemed like it would be reat, except the reviews mentioned horrible battery life (and that would surely drive me insane).
Dunno, I think I'll wait for the next generation of iPhone. I can hate my phone for 2 more months.