Today was my first day "out and about" with my new BB, and again I was struck by some differences between it and the iPhone. I was at the library (should have been studying for the LSAT, obviously wasn't), and I was signed into the included MSN app (pretty solid for a free app - you need to get BeeJive on the iPhone to have anything close to a decent IM app)... I loved the way I was able to chat on MSN, and then if a text came in, quickly switch over to the SMS app to reply to that (BBs have an application switcher - kinda like hitting command-tab on a Mac - to quickly switch apps without going back to the homescreen). If I was doing the same thing on my iPhone, the lag between switching between apps would have driven me nuts - a few seconds to open the SMS app, a few more to re-open BeeJive.
After an hour or so of IMing and texting on the iPhone, my battery would have been almost half dead... the BB didn't even change the meter after all that use.