Stores will in a lot of cases purposely de-tune the cheaper priced TV's. They draw you in with the lower price in the ad, then when you are disappointed with the image, they steer you to "a much better TV" for "only a few dollars more".
Amen to that.
First thing I did with any set I was interested in was try to get to the setup controls and adjust everything to neutral/50% so that whatever sets I was comparing were on an even keel relative to each other. I hated trying to compare sets in Best Buy because they're all mounted high up on the wall where you can't reach them.
I ended up buying a Westinghouse LCD at BJ's Wholesale Club specfically because I could adjust the controls in there and it looked fine, which confused me because I remembered the same set in BB looking horrible. Then I went back to BB and after staring at the wall of sets I realized that ALL the Westinghouse ones - and ONLY the Westinghouse ones - were the ones that looked washed out and colorless.
BB isn't interested in selling you something good, they want to sell you what makes the store the most profit. If you insist on buying something cheaper, they throw a guilt trip on you like they're doing something wrong selling you what you want.