Opinion's on Plasma PQ or Size

[cidman3]

I have a Best Buy Pioneer 5020 in my Den.

My view distance is aprox 6.5 feet. The lighting is mostly Dim (day) to cave-like (night).

I am debating returning the 5020 for a Panasonic TC-P58S1 for the extra size.

Is it your opinion that this would be a move that I will regret due to a loss in PQ or is the PQ loss minimal compared to the added picture size? I ask because I have never owned a set larger than 50".

Thank you.