And I believe the 600Hz refresh rate of plasmas isn't a comparable stat to LCD's refresh rates. In general, plasmas do have less motion blur, but I don't think it's something your really going to notice much of a difference with for the Vizio at 120Hz. Most reviewers agree that 240Hz really makes no big difference between 120Hz, so don't buy into that market hype.
That said, I have a Panasonic plasma and love it. It's 2 years old I think and it's been great. I trust Cnet's reviews as well. With a lot of natural light though, you may want to consider the Vizio as LCD's get brighter. I've never really read about a good breaking point for when a room is too bright for plasmas. That said, if you buy from Costo, they have pretty stellar return rules, so you could try out a plasma and see if it's ok.
The one thing I recommend too is to check cnet's calibration guides to get the best picture quality. See link for Panasonic's
