They suck, well they dont suck as far as build quality and durability. What sucks about them is that when you unscrew the nut to loosen the base of the rings so you can remove or put them on, all the pieces fall off unlike other rings where the bases cant even come off.
I would say pass on them and get the burris tactical rings. I have leupold mark 4, Burris tactical and the Blackhawk tactical and feel the best ones for the price are the burris. BUT if you do decide on the blackhawk they work fine if you dont mind dealing with all the pieces of the base falling off when you loosen them