I would be looking at Vizio's P-series and TCL's 5-series since they typically offer best value and best picture for the money.
I think you might have meant the TCL 6 series (55r617), and I would avoid it like the plague due to vertical banding issues aka Dirty Screen Effect. Best buy have this as low as $729. The 5 series is a MAJOR step down in TCL's line and reflected in their cheap price~$600.
I bought my new LED tv about a month and a half ago, it's a Samsung 55nu8000, was $848.00 plus tax, $999 at Costco who wouldn't match Visions price. I chose it over the Vizio P series at Costco primarily because Vizio has had some spotty quality issues.
The picture on my Samsung is fantastic and it upscales extremely well. The Vizio doesn't score near as well on Gray Uniformity, which is important if you watch a lot of hockey or other sports, nor does it upscale as well as the Samsung. Visions Electronics offer a 2 year warranty on the big brands.
There isn't an LG tv with near as good a picture until you are spending around $1300 and a comparable Sony (but a bit better) (XBR55X900F) is about $1400. Sharp are now made by Hisense and I wasn't impressed in comparison.
Here is a website where you can compare tv's, they do NOT accept free tv's from manufacturers and are 100% objective, their results mirrored mine when seeing these tv's in store.
P.S. I agree with ExDilbert that OLED have a much brighter and darker picture but if you plan on using this as a PC monitor or for gaming they are prone to burn-in, which LED aren't.