We have 4 Vizios and 4 Samsungs. The Vizios are excellent. The only issue I have with Vizio is the the remote control quality is much lower than average on their basic sets. I actually went online and bought a few extra Vizio remotes to replace them as needed. They were really cheap on Amazon so I figured I better stock up. In the first two years I have had to replace two remotes.
The Samsungs are flawless except that there is no browser on the cheaper ones. You can access Netflix etc. through a bunch of preloaded apps but you can't go to any old web site and watch something. That has been annoying when trying to watch a UConn game online a few times.
So, I'd say Samsung is a hair better quality based on remotes. If this will be your main TV I'd definitely make sure any Samsung you buy has a browser. I would not buy another web enabled TV that only works on preloaded apps.
We have two high end sets from both makers and overall quality is great on both. The Vizio picture quality is top notch these days. Also, the Vizio sound bar with separate subwoofer is mind blowingly good for the price of around $250-$279. We have parties and will often have a game on the TV and then segue into louder music as the night wears on. The sound bar and subwoofer end up providing the tunes much of the time rather than my very nice stereo, which is wired throughout the house to built in ceiling speakers. It really kicks ass. I bought it on a whim at Costco 5-6 years ago only because they had one on display and it sounded great. My wife wanted to put surround sound in the family room but I didn't want the clutter or expense since we have a home theater set up in the den. I bought it for her as a gift and she was skeptical, knowing I was trying to avoid buying a second big, expensive surround system. She has never been happier with a $250 gift than she is with the Vizio sound bar and sub. Highly, highly recommend, even to audiophiles. It is that good of a product.