After using my phone last night with more than average use and the battery kept on truckin I think I'm happy with ICS for now. I did love how smooth JB is but it seemed to really drain my Nexus S's battery pretty bad. Actually, within a few hours last night I was on fb, using google, and taking a ton of pictures and by the end of the night my battery was at 52%, with the Nexus S it would have been almost dead so I'm super thrilled about that.
I actually figured that I'd just put the screen timeout on 2 minutes that way it would stay on longer, I usually manually turn it off when plugged in anyway so that's working well for me so far. The only thing I'm not happy with is when I plug it into my computer I cannot make it turn into a USB drive like I could on my Nexus S so it ended up adding all my ringtone files into my music folder so I'll have to figure out how to get that straightened out.
I do have to say I'm kind of annoyed that every handset can use the same OS and look completely different. ICS on my NxS was completely different than on the GS2. It's kind of like being able to walk into any Walmart in the country and know exactly where something is because they're the same everywhere. I appreciate the differences in models but the OS should have a standard feel to it. IDK, maybe it's just me...