I've been curious for several months now about the price differential that existed between the 553 and 554. This is getting moot, I guess, because these models are, apparently, now discontinued. It's strange that the Vizio site still shows them, though they have "out of stock" signs by them.
Anyway, I have noticed that Consumer Reports highly rated the 553, yet the 554 is rated much lower. They're rated in two different category groups; the 554 is rated in a separate group with the 3D tvs. Apparently the 554 was downgraded due to its lower rating for its 3D -- the picture quality is still shown as excellent, and all marks are the same as with the 553. The only difference is that its 3D is only rated as "fair." For this reason, the whole set is rated lower than a number of other 3D sets. Interestingly, Consumer Reports made the comment that 2D performance may be a good reason to select a 3D set, even if the 3D performance is not as good as others. Seems very true with the 554.
Consumer Reports does make a difference, and over the years I have noticed that many times their highly rated items do become more popular in the marketplace. I would suspect that the 553 sold a lot because of the Consumer Reports high rating, and Vizio upped the price to take advantage. The 554 didn't get the same kick, and it's price was actually lowered, to the point it was well below the 553. Of course, as we all know, the 554 is probably a better 2D set than the 553, given its different screen which seems to give more contrast, and its higher refresh rate. Not to mention that it seems to have fewer problems. Just a theory, but sales had to be the reason for the counter-intuitive price differential.
We've had our set since the first week in February, and have yet to even try the 3D. It's not that important to us, and it's not why I bought the set. When I bought our set, the 554 was still several hundred dollars more than the 553. But later on, when the price started coming down, because of the oddities of the marketplace, the 554 was a steal, and what most consumers apparently failed to realize was that it was in fact a better TV and a far better deal than the 553, with the 3D availability to boot.
Some folks above have mentioned the newer LCD LED sets from all the manufacturers are foregoing full backlighting, in favor of edgelighting. CNET talked months ago about this trend coming. Although edgelighting has progressed, I think it's clear that full backlighting is superior, and have read about this trend (including in Consumer Reports), and the generally lower picture quality of the edge-lit sets.
So......enjoy your 554s. We're certainly enjoying ours. One thing's for sure -- picture quality is greatly dependent on the source. Some are much better than others. Even on the same broadcast there can be differences. For example, in watching a football game over the past weekend, it was easy for me to see the difference in the different cameras being used. Some were better focused, and had the color adjusted better, than others. I don't know how much better TV I need, when the 554 is detecting variations in the cameras!