The Toyos are a bit more coin than the MT/r's however Im looking to buy soon and the MT/R's are backordered from goodyear for a good 4 weeks, I have called around and NOBODY has them in stock.
Wal-mart carrys MTR's. at least the one up here does you might want to check it out. i know the one up here has a couple seta of 37's for like $900.
i would go with the toyos. they are great tires, i love mine and wouldnt put any thing else on it as long as its a daily driver. ive never personnally ran MTR's but ive had a couple sets of bfgs and the toyos are way better. im running the 35x13.50x15 and like i said there awesome and they havent let me down one bit. also i dont know if your interested in going any bigger but from 4 wheel parts the 37x14.50x15 are actually $20 cheaper per tirehttp://www.4wheelparts.com/4wp/products/productLine.asp?cat=TIR&prodline=3665&catName=Tires&man=TOY
86 4 Runner SAS, 37 inch Toyo M/T's, E-Locker rear, Lock Right front. 30 spline Longs, 5.29's, Dual Cases, Warn XD9000i