...so I've decided to return the set and go with the 55" LM8600 LED model.
Basically, the screen is slightly offcenter; i.e. the bottom and right sides are not flush with the bezel by about 2 pixel widths, unlike the top and left sides of the screen. I love the picture, and the matte plasma is phenomenal, but at the end of the day, I'm going to go with the 55 LM8600 paired with the LG NB3520A sound bar.
I viewed the Passive 3d technology in-store (just turned it on while the Sixers-Bulls game was on), and was absolutely blown away by the quality. Seeing that, I've opted to with the LED model, even though it's a slightly smaller screen.