A lot of the bigger retail chains have at least one knock-off brand that's basically an "inhouse" knock-off. I know best buy has one, I know Fry's has one, I would not be surprised that Wal-mart has one too. They are junk, period. "You get what you pay for" is a very accurate phrase; the only exception being buying something at a reduced price due to a sale, discontinuing, or some other reason. The cheaper stuff IS cheaper for a reason, because it's not as good as the more expensive stuff.
There are also the company's who will make a cheaper version of their own products and sell them to Wal-mart, some leave their name on it for the brand recognition. Henckel's knives is a great example of this. They're one of the best knife companies in the world, and they released some really cheap quality knives to places like target and walmart just to capitalize on their brand name. There are also other companies that have made brand new companies to sell their cheap-quality products, so that their main name isn't tarnished. Visio's one of those companies, it's Sony's shit company, hence why they suck so bad.
As for Sony themselves, their TV's are pretty good, especially when you get to the higher end. Yes, there is much better, but they usually cost a whole lot more and those companies aren't doing that well. Sony's audio, on the other hand, I wouldn't touch with a 20-foot pole. I get tons of customers who see a Sony HTIB or receiver and tell me how great it must sound, when it's a piece of shit and there's much better stuff for roughly the same price. I always laugh(sometimes with them right there) at the customers who tell me they have a "great sounding" home theater from Sony.