The best way to find out if issues exist on certain HDTV sets is to select your desired media and request store owners to test them out on your own. With nothing much to lose, at least you would know if you are buying something that will not later on render some issues and leave you scratching your head.
Leading stores like Best Buy may not mind at all as long as you are a sure buyer. Though not all may be cooperative, at least you know there is nothing to hide as far as quality issues for such TV sets is concerned. Fill up the TVs with pictures as much as you can and put them their features to the test. This is a smart way to check potential HDTVs rather than relying on various reviews or marketing gimmicks hurled your way.