Stock battery gets me through the day with auto-brightness, perf set to "normal," auto sync on, GPS on, and 4G on. So I haven't done much to conserve battery life, but I do think you need to turn the performance setting to "normal" to see the life big improvement relative to the TBolt.
I've not noticed a single hiccup from using the "normal" mode, even in fast-paced games and so forth. I have also noticed that the battery really has to condition for a few cycles to get it's full performance- Run it down all the way, and then fully recharge it for the next use.
I've thought about turning off GPS since I don't use it much- just when I need it, really, but I sort of like the silly localiztions, like the weather widget knowing where I am... That would help even more, of course.
Right now I'm using the extended battery because: (1) It was dirt cheap (2) I like the feel of the phone better with the edge-wrapping case and the extended battery cover filling out the rear (3) It's kind of nice not even seeing yellow if you forget to charge it overnight, or have a heavy use day.
(For my normal use, the extended battery lasts 2 days. Definitely into the evening on the second day, at least, if not quite the "full" day. I usually plug it in over night, though, and the extended battery is typically still in the 60% range when I do that.)
I'm waiting to see what other cases come out for the extended battery, though. I've thought about seeing if I could modding an Otterbox Defender to make room for the extended battery, but it would be easier to just run with the stock battery. I might just end up using the extended battery for traveling.