Great unless you need to attach things to it. - STNGR VYPR M-Lok Free Float Handguard for AR15/M4

Now I own 2 of those rails and feel that I could review it fairly. You get what you pay for, its no high end manufacturer rail.
Look, its lightweight and looks cool and if you just using it for bench shooting its totally fine. However, the Mlock cuts are out of specs, difficult to attach pic rails etc, takes a lot of wiggling to get mounting hardware through the cuts, easy to take finish off the rail in the process, to be fair when you get them in they stay, however it feels like you are bending the rail while tightening the screws, rail material is too soft. Rear QD sling attachment hole is fine, front is a joke, it does not lock QD head tight enough. I attached my Blue force gear sling to it, shouldered the gun, QD disconnected, gun dropped and my Delta Stryker $800 scope hit the ground. Nice!, you can imagine what I had to say about it. I tried magpul/ bcm/ cheap sh*t heads, nothing stays in, i guess hole is too big and again material is too soft. Ended up spending another $20 on Magpul sling qd base. Again, its a $100 rail, but you can get LaRue for $20 more and never have any of the above issues. Hope it helps.