I would put it a small step down from Maxped in terms of durability, but not in terms of quality. The reduced durability is becuase it doesn't have as much weight to it- SpecOps is only significantly overbuilt compaired to MaxPed's massively overbuilt. :P I've used their gear for several years, after being introduced to some that had been used by friends in various branches of the service. If those guys can't break it, nothing short of artillery or air strikes can. I'd put it solidly in the same class as Tactical Tailor, ATS, the lighter Eagle and the better Aites items.

As for attaching the d-rings, look at the image here (not going to hotlink it from their site). Look at the top of the backs- you lace the straps through the D-ring, then down through the backs and close them. It would ride "flatter" to your side than the usual side mounts for D-rings. (You could do the same to any of the molle-type gear, but I think the system that SpecOps developed is one of the most robust and versatile variants without as radical a redesign as the MALICE type.)

Or you could just lace them through the webbing to make a "belt loop" big enough to mount on just about anything. It doesn't have to be flat, I've hung X-6s off things like lengths of pipe and cross braces for bunk beds.

I'd post a picture or two, but the camera isn't with me right now.