As long as you know what you are putting on a stock android image it should(TM) be fine in my experience.
Battery life isn't great compared to a "feature" phone but not horrible. GPS is really the big killer from what I've seen. When on 3G and using gps for navigation it probably will, depending very heavily on signal strength, only last 6-8hrs by my estimation. Of course this was also keeping the screen on (auto brightness) and gpu usage fairly high to draw the all maps.
If I leave data on all day(both wwlan and wlan) with only occasional gps is is usually(TM) around 20-25% at days end. Not horrible, but we know Apple and Win7 have done better. I'm assuming it is Java so there seems little Goog can do about it now...well, if they used native code for THEIR apps then at least you could get an android experience that had good battery.