Funny, as I prefer the URX 2. The 3.1 is fantastically light, but I don't like that I have to buy extra stuff to make it work the way I want, like a KAC handstop. Plus you're fairly locked in to light placement. What I do like about the 3 vs the 2 is being able to put a front sight where I want and not losing several rail spaces due to the flip up sight.

Either way, you got a nice rifle!