If you buy a Samsung, they are all basically MAP pricing, so everyone will have the same price.
As far as Vizio and other brands, I haven't had a whole lot of experience with them.
My Samsung UN65JS8500 is amazing and has fantastic picture quality. UHD 4k up scaling works decently and I cannot complain about the TV one bit.
The fact I got it from Amazon and they shit the bed on delivering on time made it frustrating, but I was able to get free gas for 2 people for over a month with the Giant eagle fuel perks, so I was more annoyed than anything.
Seems like 4k will be a real thing shortly, so If you are buying a TV to get you though, it may not be worth it, however the 4k train is coming. I would say in less than 3-5 years 4k will be as common as 1080p is today.