I have the Vizio M651d-A2R, which I believe is just the updated version of the 65 in. 3D TV shown here by Vizio.
I paid a couple (read: a few) more hundred dollars for mine new, but I did mine for the peace of mind. I am just not a fan of expensive refurbs. But I will say, that I am completely in love with the TV.
The picture quality is fantastic, rivaling Samsung which is my current favorite due to their brightness and typically matte screens. My Vizio has a reflective screen, which I don't particularly care for, but I thought it would be a bigger deal for me than it is.
As it stands, the 3D works well from any source that can output two separate screens. So say you download a "3D" movie from the internet, but your computer isn't actually 3D so you can't play it on your screen. Just hook up via HDMI to the TV, and click the 3D button on the remote and the TV will lace the images into one 3D image that really pops. I am very impressed with the passive 3D TVs that have been coming out--it's just like going to a theater!
Mine is 240 hz, so I can't speak much to this TV and won't about the refresh rate. If you're in the market, you likely already know the differences and are comfortable with your selection if you go with 120.
The apps on the Vizio TV are nice. A friend has a Samsung smart TV, and the apps work a little better on his. Firstly, first-rate selection is a bit better (think HBO Go), but really it also comes down to interface. Vizio's interface is a bit clumsy, having a customizable selection available through a side-scrolling event, and the rest available through a separate interface that is easy to work but just a bit frustrating. First things first: take off all the Yahoo apps and other garbage from the "Your Apps" selection, pick a few you'll use, and you won't be bothered with it again. Really, it's not that bad. Just not as polished as Samsung's.
Some have had concerns over the edge-lighting that Vizio has used on these TVs. I only notice on dark (black) pictures. Everything else is great. The blacks aren't perfectly black, but I haven't tinkered with the settings much since getting mine a few days ago.
All in all, mine looks different and is definitely a different version, but I think they are comparable, and if you are comfortable with refurbs, then give it a go and see what you think. I feel slightly uncomfortable talking about a TV that isn't actually 100% on there, but I hope I could give a little bit of insight as to what to expect with the M3D650SV for sale on Woot! Good luck and happy shopping!
And for all my time, Woot! servers are acting up. Grr. I will try a few more times but sorry if it goes through more than once!