There is a known black level issue at least on *some* of the G10s that have been sold. It might let the wind out of your sail at least a little, depending on how picky you are regarding maximizing the black levels for viewing. Pop over to AVS forum in the plasma section for more details. Other sites have covered it as well.
That said, both HDTVs are quite good IMHO, and have PQ which tends to blow away the majority of the LCD models currently sold. Which one has the most 'real' picture is always going to be subjective. The content you watch plays a huge role (cable or satellite, Blu Ray, standard DVD, Standard definition vs High definition, etc.). One size fits all really isn't possible as such.
So I have essentially narrowed my choices to these two for a HDTV where my main hope is simply the best picture--good blacks and most natural colors (would it be worth throwing in the Panasonic V series, or waiting for their new models with infinite black?).
Their reviews both seem fairly close. While the Samsung is slim, that is a feature I could care less about. Again, I simply want the best and most real picture! People keep trying to sell me on the THX certified picture of the Panasonic which is tempting, and the smaller price tag, but price isn't an issue between the two..just picture.
Any input is greatly appreciated...whether you are a user of either TV or simply familiar with the similarities and differences between the two.