Picked up the Nexus-S last week, and not looking back Battery life is million times better than the EVO, almost on par with my Brother's iPhone4. And the Super AMOLED screen is drool worthy, need to wear a bib around this awesome phone. 2.3 Gingerbread is a nicer and more polished update to the Android OS, can see it is maturing finally, and getting better with each release.
I am open to an iPhone 5 this summer, but they need to do a few things to win me over, again. Make the i5 with a slightly larger screen at 4". Add widgets to the iOS. Add a solid notification system. Do those three things and I will jump back onto Apple.
Right now this Nexus-S is so fast and smooth, amazing phone. I love my "beautiful" clock/weather widget at the top of home screen, and my star field live wallpaper, phone looks very sci/fi but still business like mature at same time.
Sure the plastic casing might look cheap, but it feels light and solid, but no it's not the bad ass looking iPhone 4. But to me only the iPhone 4 looks great, the 3G + 3GS looked lame and too rounded plastic.
I'm simple, iOS to me is much more polished than the counterparts. Notifications I can live with because of the polishness.
However the only thing I envy is a larger screen.