I don't think it's a problem of PR 1.3 but rather of the update process. When I updated to PR 1.3 I had the same problem (I didn't use any modifications or software which would drain the battery): Bad battery life & overall laggy impression of user interface.

I decided to re-flash the phone (full reflash with emmc firmware - over-writing the firmware didn't help!) and all the problems were gone. For months now my system is butter-smooth and battery life is back to normal.

So I couldn't figure out what caused the issues and I know this is no easy solution - but that's how I got rid of it...