There are 17 key features
missing in "pure" Goggle phones. the Galaxy S II has all of the basic features plus
25 features that put it way out in front.
I just got the Epic 4G Touch with almost identical TouchWiz 4.0, Gingerbread, and features. It is amazing.
If your idea of fun for a weekend is to try to figure out a way to make Facebook work, the Nexus S is the phone for you. If that would be the weekend from hell, don't get a pure Google phone. There are 16 other issues just as big.
To me the sad part is that AT&T salesmen don't tell the customers the basic features that are missing in the Nexus S. Maybe it seems funny to do that or maybe the sales people are just that uneducated.
Many Nexus S problems can be fixed with rooting but some simply can't be fixed. Still the average person will have no idea what to do and no desire to do it even if they could.
The Samsung Galaxy S II works right out of the box.