For 30 years I only bought Sony. Now, I will likely never buy another one. Nothing wrong with them, it's just that they are expensive and I am not a videophile so paying for the excellent Sony picture is not worth it to me (I want save that money for my audiophile obsession). In the last three years I purchased a Vizio 50" Plaza and a 52" Magnavox/Phillips LCD. Both working great with long hours of daily use (knock on wood) and were extremely good deals purchased around Thanksgiving.
Many people buy from off-brand sets from the big box warehouses due to their buyer protection plans. I think the plans are not as generous as they used to be (due to customer abuse), but still quite good. You can also buy an extended warranty, but then your back to the top-brand price (although w/o an extended warranty).
Do your homework and know what you want and what you are getting (ie not the best picture/sound/menu/etc), buy from a warehouse, buy and extended warranty if it helps you sleep at night or cross your fingers and take the risk. Yes, you can get a great deal buying off-brand.