In the world of 55", LED, 120 Hz. TV's.....?

You have no idea how complicated this answer can be.

Problem number one, only a handful of companies actually make LCD panels, but there are hundreds of brands. That Sanyo could have an LG panel. Sony, LG, Sharp, Samsung and a couple that make panels, and aren't brands that you would know actually make panels. I don't recall if Sanyo actually makes panels.

Vizio, one of the most well known brands makes zero LCD panels. they buy from several makers.

Now back to your question, without model numbers it's harder to say. The LG could be an 8th generation panel, the Sanyo could be a 6th generation panel by any number of makers. I've never seen Sanyo get a killer review for an LCD TV, so they are probably buying older generation panels to keep the price down and pass the savings on. Oh and by the way, I use the term LCD because there's no such thing as an LED TV, they are just LCD TVs. Instead of CCFL backlights, they use LEDs. LED is a marketing term, and in some countries TV makers have been banned from using the term "LED TV" for fraud reasons. But here in the USA, it hasn't been an issue.

If the 250 isn't going to break you, go with the LG, it's probably a later generation panel. Don't pay extra for LED or 120hz, neither will give you better image quality in and of themselves. These features are generally used in later generation panels so it can seem like they are making the image pop more, but it's the panel not the LEDs or the refresh rate. good luck.