I'd look closely at Rtngs review.

http://www.rtings.com/tv/reviews/sony/x900e

http://www.rtings.com/tv/reviews/vizio/p-series-xled-2017

http://www.rtings.com/tv/reviews/vizio/m-series-xled-2017

They really have quite a bit of detail. It should help you figure out what if best depending on what content you view, like if you are interested in gaming, sports, movies, etc.

I'm looking for something in this size this year as well, also from about that viewing distance. By my main use for the TV would be more casual viewing when I want to be able to have the lights on. I'm strongly leaning towards the 75" Vizio p-series. For watching movies I want to get a drop screen and projector with about a 120" screen.

If I were only getting a tv I might be tempted by the Vizio M-series. The performance is close to the Vizio p-series, but you can get an 80" screen at a reasonable price. Performance is important, but size is a big factor too.