See my top-level comment.
* Graphics issues are fixed in 10.8.3 (still in beta). It appears that the drivers have been rewritten from scratch, this was the worst beta seed series I can recall for any OS X release, ever, with new seeds days apart, seeds that were completely broken, kernel and graphics driver instabilities, etc. The latest seed is much improved and should address this issue.
* LG panel ghosting: I had my clamshell replaced a few months ago. There was a new part number, it has been officially "fixed."
* I have hisses and pops when listening via headphones, but not over the speakers
* Power management: Finally fixed with latest firmware updates + 10.8.3 + reset NVRAM/PRAM and SMC. Firmware updates plus NVRAM [0] and SMC [1] reset will likely fix it for you.
0: http://support.apple.com/kb/HT1379
1: http://support.apple.com/kb/HT3964