part brand preference, part past purchase history, part knowledge.
a relative was an electronics technician for 25 years or more... and said that the easiest repair parts to get were for sony since they stock them. parts for brands like vizio, olevia, etc are very difficult to get.
i've owned quite a few sony products before and i've had good luck with most of them personally.
i own a sony ps3 so it plays nice and control functions work on the controllers without me fiddling with it.
the price was right. when i bought mine i got a $2000 tv for $1200. current sales and prices arent bad as well as i stated in a prior post.
however that is just what i personally would get. i've heard that samsung isnt a bad choice also but i would avoid no-name discount television brands as they are not worth the trouble. some people have had good luck with them but personally i dont feel they are worth the risk.