Updated mine, it's too early to tell if battery life changed at all. Haven't run into any bugs, and it's basically just a few minor changes. Customising the lock screen is basically the only thing of note that I noticed.
It's only been not even a full day yet. Might be a bit early to ask.
Battery life could be hard to say until a few days in. If they made changes to the algorithm, then it would need time to relearn your pattern and for people to actually notice.