personally I'd rather use a physical keyboard, that way i'd know when I keep hitting the n or m keys instead of the space bar and ending up with stupid words that the dictionary doesn't recognise.
I like the on screen keyboard of the iPhone. It is the most accurate onscreen keyboard I've ever used with the exception of Swype.
I like typing on the on screen better than physical because it's quiet. As lame as that sounds, I don't like everyone around me knowing I'm typing. With my old Storm 2 (which had a very loud tactile feedback with the click screen), I couldn't type without annoying the wife. Her physical keyboard on her phones (8330) were loud too.
After 4 years the virtual keyboard is now part of my brain. Never going back to physical on my phone. I also think it's easier to type with one hand on the virtual keyboard than to try and use one hand with a physical keyboard like on the BB.
I never want to use a physical keyboard again. It took me about a week to get used to it, but now I type just as fast if not faster then I did on my old Berry.
Not having a keyboard was my biggest concern with switching from BB to iPhone. Figured I'd use the ip4 for the 30 day return period and make up my mind. (That was in August!) When I had to wipe my BB prior to selling it, I couldn't believe the amount of force I had to use to type on it! (Go ahead, call me a wuss! My husband does all the time!) LOL!