LG screen : possible Image Retention which, unlike Image Burn In, fades away in a few minutes like on most modern Plasma TVs. Other than this, the LG screens have great uniformity!
Samsung screen : Doesn't seem to be plagued with ghosting / IR issues, but has tint and light bleed issues.
Pick your poison! I'd take a LG screen over Sammy any day!
Unless you have major IR issues, just forget it and enjoy the damn computer!!!