I have not had issues with mine although I have barely used it...under a thousand rounds on it so I would not expect any problems to surface. Still, I don't really expect trouble.
Honestly there's not much to go wrong. The most you could really do would be to pull a helicoil by cranking it down too hard, which would be possible on lots of rails, theoretically, but it rarely occurs.
There's about 12 to 1500 of them out there and I have not heard of any rail issues (although I am not saying none have occurred, if they have I'm not aware though)...talking to Jeff last weekend (owner of NEA) and I recall him saying one thing they'd been happy with was the performance of the rail.
Some guys didn't like the look of the attachment method. I also recall that when they first came out some people were upset that there were only short rails on the sides, right up at the front.
Ironically that is now pretty common. Somewhat humourously, NEA were really ahead of the curve on that, not that I imagine they'll ever get any credit for it. But if you look at rails now vs when the NEA rail first hit, they've kind of gone that direction. It used to be all-rail on every surface, like the URX 1 or DD Omega etc. Now it's hip...check out the KAC URX III and tell me it's not just a more elegant NEA rail.
So anyway if you can get a deal on the NEA rail and you are fine with the appearance, in a strange way you're actually getting something kind of advanced for dirt cheap.
Life is funny.