I have an iPad 2 and a Nexus S and my GF has an iPhone 4. I build iOS apps. I know my way around the cocoa API and the devices and for day to day use I much prefer my Nexus. The deep google integration is fantastic and vanilla android on the nexus is a polished experience (sans hardware accelerated animations), much more so than all the crappy OEM interfaces.

I'll give you fast/smooth, but from now on, I can't see my next phone being anything other than a Nexus.

Google Maps with Voice Navigation was the killer app that made me ditch iPhone 3G for Nexus One. Now with Nexus S, I haven't looked back.

If your digital life is in Google apps, a Nexus phone is a very sensible choice.

I'm not willing to put up with carrier crapware on non-Nexus phones though. That would be too big of a compromise for me.

Apple has built a certain brand image about people who use their products. There are many people who will gladly choose Android to avoid being identified with that image.

That is not to say that Android has no virtues of its own. I prefer Android for more than just brand identification.