I've been long time HTC & Nokia user (I currently have E71 as main phone and E90 laying somewhere).When comparing to BlackBerries or MS phones, I'd most definately take Nokia... But when it comes to iPhone....
... since my co-worker bought his iPhone year or two ago, I've been wanting one as well! It is the smooth UI and excellent (touch)screen which makes it so nice little machine and relatively intuitive to use.
My E71 may have better battery life, and specs in non-game area are quite similar. I've even become used to it's calculator looks and it's small buttons (which makes typing quite fast). GPS/Camera etc. feels better than those in iPhone, but they are more than adequate in iPhone too - and when you add to that the excellent web browser and how it works in iPhone - it simply works! I know what my next phone will be!