I bought this past Friday and just set it up last night. I was originally going to get the Vizio M552i-B2, but decided to go with this after learning that this one is native 240Hz, where as the Vizio advertises 240Hz, but it is not native. The Best Buy salesman also said the Panasonic has IPS and it Vizio.
I'm sure both TVs look great once you get them home, but I am happy with this purchase so far. Still lots of configuring and personalizing to do, but that is fun for me. It definitely has a lot of features, apps and screens that you can move around, similar to using a tablet.
The picture looks really nice. Will update more later.