in any Blackberry I've ever owned or seen in smoothness, intuitiveness, app switching, ecosystem, and whatever else you can think of.
There is a key qualified there, that you've "owned or seen". The new BB7 devices really don't get the credit they should have and very few people know them. Everyone seems to have missed that RIM changed their UI over to 60fps hardware accelerated rendering. The result is an experience far smoother than the vast majority of Android devices. Things like pinch zoom in the browser are as smooth as iOS.
I'm not going to tell you that BlackBerry has a ton of apps, I'd be deluding myself. But the IM, email and social networking experience the GP was referring to is really unmatched by other platforms.