Vizio has gotten a LOT better than they used to be. That still doesn't put them at the top of the ladder though.
There's nothing wrong with edge lit on a quality display. I have zero issues with mine off axis even with 3D, but how often do you really sit far enough off axis for it to be an issue? Yes there are times when you might see the edge lighting on dark scenes, but on the whole, I don't see it as a big issue. If you see it obviously all the time, you likely have it turned up too high. A full array would drive the price up quite a bit IMO, so while it may be better, the downside is it probably wouldn't sell well either due to cost.