I do occasionally have the screen dim issue on this build, but the real annoying problem is that I can not hold Shift or Alt key and press the other keys to get the character I want, I have to press Shift or Alt and let go and then press the key, a pain when doing a series of numbers in a password :-/
Running 402 on att & 9810. When i internet tether from playbook, it won't pick up the IP address like it did with earlier releases of 7.1. I do have tethering plan from att.