I'm not sure how much cheaper they are but Oakley also do their Flakjacket and Flakjacket XLJ shapes with a prescription lens that is not a weird insert as with the Ms. I got some of these last year and they have been brilliant. Ace coverage and the lens is shaped right to the extremities so looks a bit thick at the edges but you lose no periferal vision.
In reletive terms even Ms are cheaper than a mid-range suspension fork so it's probably a worth while investment.
In reletive terms even Ms are cheaper than a mid-range suspension fork so it's probably a worth while investment.