TechCrunch review:
http://techcrunch.com/2010/12/06/google-nexus-s-review/
However, I do imagine that the AMOLED display will not draw as much power, so it might indeed last longer.
My Evo can go at least a day and usually most of 2 days on a single charge. I use FreshEVO Firmware, but there are other options too.
from a recent review by Anand:
http://www.anandtech.com/show/4045/lgs-optimus-7-samsungs-fo...
Also, AMOLED will only be more efficient if you view dark screens more often than bright ones, which I don't think would be true for most web browsing.
Update: eliminated shortened urls.
Edit: Thanks for changing it!