I recently purchased, and will soon be returning, a 40" Vizio M Series. The reason for returning it is because it has a strange 'flicker' in the bottom left part of the screen every minute or so, which apparently might be a common enough defect that simply exchanging for a new unit of the same model # wouldn't solve the problem. I also wasn't that happy with the black levels or flashlighting. Luckily I purchased it from Target so I can just drop it off and get my money back.
I can get (via Amazon Warehouse Deals), a "like new" 40" Samsung 6300 Series for only $100 more than what I'll get back from the Vizio, but it won't come with a manufacture's warranty and I won't be able to return it unless it's completely broken. This would max out my budget but I'm not finding anything else around $500 that's reviewed better than the Vizio I already have (except for the Samsung 6030, which apparently has backlight banding which, imo, is worse than edge flashlighting).
My research keeps pointing me towards the Samsung 6300, but it's out of pricerange unless I go for a "like new" unit from Amazon without a warranty.
Can anyone comment on how much better the picture quality is going to be on the Samsung, so I can decide if it's worth the extra $100 plus risk of no warranty? Unfortunately I'm not finding much to go by with the various professional review sites other than to say that both "have excellent PQ for the money".