Just stuck it on the ghetto fabulous scale here and it came in just under 13lbs with no magazine, a harris bipod mount, the VLTOR stock, and 2x BUIS (so pretty much how it's pictured above but I put the bipod block on it, but not the bipod).
Yea, I've shot the AR with the PRS. I actually like it, the PRS stock is down right awesome once you get it configured the way you like it (eye relief, comfort, etc). But, that being said, I have never shot it with the PRS in a "tactical environment" (ie: Carbine course, CQB/C, etc). I put the PRS stock on it in the first place to just to try it out, never intended to have a 16in carbine with a PRS stock on it. Then I find myself TDY at Altus and forgot I never put the M4 stock back on and all my other gun parts are in long term storage.
My next rifle build will be a Mk12 Mod0 clone. The M1A actually came with a PRS stock (bought it used and have a box full of goodies). I will put a PRS on the M1A since I will pretty much only use it for distance shooting, slap the VLTOR that is on the M1A onto my existing AR, and then take the PRS on my AR and use it for the Mk12 Mod0 clone build.
Obligatory pic: