From what little I know, I think most smart phone users have bases with pretty much different needs.
It's pretty much a given that BlackBerry users need whatever it is that made the thing so popular. I tried my sister's Curve and hated it. But it was cheaper and could be bought without a data plan. As bad as that browser was, no biggie. She wanted it for text messages, so it should be good.
I don't know what Pre users need, but perhaps it's more of what the Palm Pilot offered. That was a kickass device except for the fact that both of mine died pretty quickly. The multitasking is a good feature if you need it, but I think the Apple SDK has allowed a lot of that while maintaining more battery life.
IMO, the iPhone is the smart phone for people who like iPods. It does music better than anyone else. It does other media better. It makes a lot of the simple things (the new video capture) pretty easy. When I got one, I pretty much wanted a phone I could use as an iPod. Apple went beyond that and helped AT&T hook me in to now an extra $35/month. I was in a mall Sunday and slowly was able to find a map from the Mall's Web site (hey, it's a 2G phone).
So I think each phone has a good market. RIM actually benefited from the iPhone exposure and sold more devices during the first year. Palm is doing the opposite by jumping on the bandwagon as a newbie. Lots of luck to Palm, but the Sprint network sucked ass when I used it on a Virgin Mobile phone.