I have the 42" GWIII also. I specifically bought it because I wanted a TV that would perform well with lots of light. It has a very good AR coating and reflections aren't an issue. It's bright enough for all situations in my room but I don't have sunlight shining directly on it.

I'm happy with the TV overall. It's flaw is a relatively high black level. It's black level is higher then then the best plasmas but comparable to the off brand ones that retail for under $3k. The high black level is only an issue at night with the lights out. When there is ambient light the room puts an effective floor on the black level that is higher then the TV's level. It's not the TV I would buy for movie watching in the dark but it's just what I wanted for a general purpose family room TV that would work well in all situations with all program material.