For me, I will stick with Vizio and buying them on Amazon for all of my TVs and here is why:
We bought a TV back in March of 2014 from Amazon and then last year it died with a popping sound. Obviously we were well past any warranty period and did not buy the extended warranty, but we called Vizio to find out how much it would cost to have it repaired, to our shock they offered to repair it for free as long as we signed a statement saying we understood this was a one time offer. Amazon was willing to help us speak with the manufacturer if necessary, but really we didn't need them at all, Vizio just made the offer.
Not only did they repair it, they had a technician come out to our house to do so and they sent him two different parts, as it could have been either part and he opted to put both parts in rather than spend time figuring out which part it was, essentially meaning that aside from the case we have a brand new TV because of the parts they were.
I have a friend who had a Sharp TV that they bought from best Buy for 15 months and it did something similar, neither Sharp or Best Buy were willing to do anything to help. I have had other friends with similar issues with other manufacturers as well, so this is why I will stick with Vizio and buying from Amazon.