The Nexus S is the new Google Android phone. It is sold exclusively by Best Buy in the U.S. for the T-Mobile network. This is my personal review of some key aspects. I'll add more here as I learn more about the phone.
Pure Android. I prefer this to manufacturer add-ons such as Motorola MotoBlur, HTC Sense UI, and Samsung's software.
Updated 2.3 Gingerbread OS. The most noticible advantage to me is that the keyboard is much improved.
Ugly in several ways
Overall the phone feels like cheap plastic.
The curved screen seems to cause distortion, as if it's a lens of glass of variable thickness rather than truly a curved AMOLED; the top area of the phone has a fishbowl effect.
The lower back has an odd bump that doesn't fit my hand well, doesn't fit into a generic case, and doesn't lie flat on a table.
The software has a pervasive lime green and flourescent orange color scheme.
Buggy in several ways
Right out of the box the phone had problems finding the T-Mobile network and the GPS. My Samsung Vibrant Galaxy S had the same problems, and the Nexus S has much in common with the Galaxy S.
The home button and search button seem to be broken: when I go into an app like the web browser, then press home or search, the phone vibrates but nothing else happens.
The first call I made, the phone app showed an error message like "Cannot complete the call". The error dialog box was impossible to dismiss, and there was no way to dial another call without resetting the entire Nexus.
Tech support is non-existent so far. T-Mobile doesn't support this phone because it's a Best Buy exclusive, but Best Buy just says "you'll need to ask Google".
Slow in several ways
The graphics are jittery and staccato as if the graphics chip can't keep up with scrolling. To my eye, the jitter is on par with the Galaxy S.
My Nexus S needs service to fix the broken home button; this means mailing the phone to Google, and waiting for Google to mail back a replacement phone. This could take several days which is much slower than a normal T-Mobile replacement which is in-store same-day.
The data speed is terribly slow compared to the other new T-Mobile phones like the MyTouch 4G. This is because the Nexus S uses the older, slower network (3G-speed HPSA) whereas the MyTouch 4G uses the newer, faster network (4G-speed HPSA+). I see the Nexus S as about five times slower, which is significant to me because I use the phone for tethering.