I have one on my SBR, and will be getting more when they come out for some other guns, what's INGO think? They are made in northern Indiana, by a local company.
So far no one has had any issues with the weight, but so far it has only been shown to various S.W.A.T. members, and local law enforcement. I will try to get the weights of the standard quad rail, and this one.
I kind of feel like if I want a vertical grip, I'll just put a vertical grip on a rail. I don't really see the value of this. Not trying to knock you down, it certainly looks cool, I just don't really see the utility of being able to hide it away (aside, I suppose, for transportation).
It's meant more for police, and military, it was designed to be less likely to get caught on seatbelts, by folding flush, as in military personnel deploying from a Humvee. I have avoided vertical grips because I don't like them all the time, and when not in use, they are in the way, at least for me. This one folds flush when I'm not using it, and feels like a rifle without a front grip, when folded.
I have more info, but I don't want it to become a "he's advertising" problem with anyone. The rail and handle are 6061 T6 aluminum, the locking mechanism is steel, it is spring loaded for faster deployment, and locks up very tight, and is only a few ounces heavier than a plain quad rail.