Heya Austin. That sucks about the M, but good choice keeping the 4Runner
I personally have had great experiences with BFG A/T's, and was completely underwhelmed by the Bridgestone Revo's (they are hyped like crazy, so I expected better overall off-road traction). You're talking about running 15 inch rims, do you have the smaller braking package which allows you to do that? You might consider getting 16" rims to allow the possibility of a Tundra brake package upgrade later...
Taking my opinion for what it's worth, the Revo's are on the street side of an A/T, and the BFG's are on the off-road side of an A/T. Both have good wear characterisics (Revo's last a bit longer), and good traction in wet, ice, and snow. The BFG's are better in deep(er) snow due to deeper tread IMO. The BFG A/T KO's of course have siping, as do the Revo's.
On an aesthetic note, the BFG's look a lot better (read- more agressive) than the Revo's, and perform far better off-road IMO; so whatever that's worth to ya. The BFG's are also usually slightly cheaper.
Good luck selling the car, hope you find some good tires for the 4Runner.