The ones I have seen, the top rail does not line up with the upper receiver. They are well made but that alone turns me off to them.

I run a LaRue FF and an MI non-FF. If you want a two piece snap on set, the MI are hard to beat. I had some YHM's and sold them to get the MI. I'm satisfied now.

As a point of reference the first set of rails I owned was a KAC RAS. They are the best, but I couldn't afford another set. So from now on, on a budet, its MI for me.