I typically use a Nexus one, but I recently had to use an iPhone 3G to do some car navigation. I have had a general preconceived notion that the iPhone has a superior UI to Android--probably due more to reading about it than to actually using the device--and I was shocked at how much clunkier the iPhone 3G felt as compared to the Nexus. Scrolling and zooming were slower, the GPS indicator of position felt significantly laggier than on the Nexus, and the screen was a lot less crisp and bright. And that's not even getting into the fact that the "car navigation" feature on Android is far superior than what the iPhone was capable of displaying. Everything felt so laggy that I rebooted the iPhone to give it a chance to reset itself to a good state (to no avail.)
Now obviously the Nexus one is about a year and a half newer than the iPhone 3G (July 11, 2008 vs January 5, 2010 according to Wikipedia), and it may be that the 3Gs is much more comparable, but the 3G was only discontinued in the past few months so there are a lot of them in the wild still. There is a perception that the iPhone is plain superior, period, but a lot of the iPhones actually in peoples's hands are really not.
Now obviously the Nexus one is about a year and a half newer than the iPhone 3G (July 11, 2008 vs January 5, 2010 according to Wikipedia), and it may be that the 3Gs is much more comparable, but the 3G was only discontinued in the past few months so there are a lot of them in the wild still. There is a perception that the iPhone is plain superior, period, but a lot of the iPhones actually in peoples's hands are really not.