I was on 5.1 for a a couple hours. I discovered that ISX caused Safe Mode when initializing (easy fix, not so bad) and that Spejngtimize 2 does not work at all.
And man do I really hate the look of the new lock screen. I mean I hate it. I do not use my camera that often. Hopefully someone will release a tweak to bring back the old double tap home on 5.1. I hate the slightly smaller sized sliders.lol. Even the slide to power off slider is smaller. But that's just me. Always liked the default slider style (except with my shiny black slider.....not gray..lol)
2 of my favorite tweaks not working perfectly, and an ugly lock screen......no thanks. I downgraded back to 5.0.1.
I have no idea if battery life was better. It drained really fast after restore, but I'm pretty sure that don't count. Always cycle charge after a new iOS install. Which I didn't do. Looks like its gonna be a while before I'm on 5.1....bummer. I hate disappointments.
Plus my battery life on 5.0.1 isn't that bad any way....just have to know how to use the device in a battery conservative way.