About two months ago, I was looking to replace my 8 year old Panasonic 32" LCD. It was a great TV and served us well. I just assumed I'd get another LCD and started doing a ton of homework on LED technology. Since I was stepping up to a 55" or higher size set, that limited my options a lot in the LED/LCD market. I had narrowed down to the Vizio you mentioned in your orginal post, and the LG55(I can't remember the rest). Both were fully backlit (rather than Edge-Lit) and had local dimming. At this point in process, I hadn't even considered plasma.
So I took my wife to Costco to see the Vizio. She immediately noticed the blooming effect. Then we went to BB to see the 55" LG and she did like that one. But she fell in love with the PN58C8000 Samsung Plasma. I was concerned about image retention and burn-in. So we went home to do some more homework. Turns out CNET ranked the PNxxC8000 second for 2010 models (behind the VT25 series) in just about every category. Now... both the Vizio and the LG were in the top 10, so that's saying a lot too. More homework on the plasma revealed that most of them now come with a pixel shift feature that helps a lot with IR and burn-in. To the point where it's almost a non-issue.
But here was the deal killer for the LED/LCD. The next day (Sunday) we went to a friends house to watch the football game. He had just bought a 60" Samsung LED/LCD and was having a party. There was no room on the couch so we sat on the floor. The TV was mounted on the wall above their fireplace. We could NOT see the picture at all while sitting on the floor! It was truly terrible... you honestly couldn't watch the game. You hear people talk about the viewing angle being so bad on LED/LCD - it really is true.
We went back the next day and bought the plasma and I'm not sorry one bit. It's a phenomenal set and the picture is amazing. The off angle viewing is great too, which is good for us because it's in our family room, which is quite big (and well lit, btw). I know that I really would have been sorry had I bought a LED/LCD set.
I wanted to share this because I'm not a plasma fanboy by any means. I just wanted a great TV and I feel like I got one. Hope this helps.