I recalibrate my batteries after every upgrade and my iPhone 5 and iPad 4 have about the same battery life as before the upgrade.
iPhone 4S - 16GB, White | iPhone 5 - 16GB, White | iPad mini - WiFi, 16GB, White | iPad 4 - CDMA/LTE, 16GB, White | Apple TV
Update: I recalibrated the battery on my Mini and did the necessary re-start. It does not seem to be getting better battery life. I will just live with that. I love this Mini.. I just hope Apple, in their infinite wisdom, will release an update soon to address that... One interesting side effect it that the Mini now goes online and finds the Verizon signal much quicker than before the update, but that could well be some of the tweaks and Settings changes I made while trying to improve the battery life...
I also recalibrated the iPhone battery. Interestingly, my older iPhone 4 seems to love this new OS and gets better battery life than before!
And so it goes...
One thing i did- right after upgrading the mini and iPhone 4 is to do a full reset (not the erase all one) and a soft reset (sleep and home button) before i started playing with settings. Both seem to run good, normal battery as far as i can tell however, safari is slightly slower on the mini anyway. I quoted your post because i also wanted to point out that my iPhone 4 is running very well, no lag not even using the "documents and data" tweak. So far I'm very happy with both and like the upgrade.