I'm 6'4", 245lbs (plus/minus 10 pounds, I fluctuate a bit) and took up running a little over a year ago - this year I have managed to complete 3 half marathons and am totally chuffed with these shoes. I'm not sure they last all the way to 300 miles before the heel collapses a little, but for cushioning and support these can't be beat. I'm only giving them 4 starts because I suspect the heel is collapsing early, but being huge I can't blame them. I'm stocking up while they're still around and dropping in price.