Anybody have experience with these?

I put a set on my f150 last month. Have about 1k miles on them. So far so good. They are quiet and last weekend when it was a muddy mess did well in the soup. They actually cleared mud well. Id say they clear better than the BFG ATs did.

I read several good reviews online and with the 55k mile warranty and $160 price tag I gave them a shot. Saved me $100 per tire. Time will tell.

For what it's worth:

I am a member of Toyota 4Runner forum and there is a thread that started in 2015 (when those tires were introduced) discussing those tires.
In 3 years, I have not seeing any negative comments from anyone who switched to Falken Wildpeak AT3W. That thread has over 1000 posts so there are many people who are running those tires… most of comments just highlighting how great the tires are and how much they like them (great traction (wet\dry), great in mud, quiet and how good they look)… a lot of those people are switching from BFG KO and KO2...

I currently have Nitto TG G2 (and like them ), but based on that thread info my next set will likely be Falken.

I run 275-55-20 are they six ply tires

The A/T3W is loaded with new features that make this tire stand out among the crowd. The tire features a two-ply sidewall, but both plies have high ply turn ups wrapping around the bead and rising back up, ending just shy of the upper sidewall tread features. This creates a four-ply thick, sidewall to protect from punctures in off-road situations.

do these make any change in your mpg

Mine stayed about the same as the BFG