Our experiences have been with the conversion kit and not with a complete PWS rifle (built from the ground up by PWS). I think it would be fair to say that the blogger I linked to has had a decent response from PWS even if the product itself has been less than satisfactory.
For my part, I had positive dealings with the owner and positive performance from their product (remember, I sent the conversion back for repair before I had a problem ... as soon as I noticed the loose gas block). It ran like a house-a-fire during the last few three gun matches I went to ... including the one I mentioned in the comments section of the blog that took place during a torrential cloudburst >>> THAT WAS FUN !!!
If I had to do it over again, I probably would avoid jumping on the piston conversion bandwagon and left my rifle alone. I would have bought a ground-up designed piston rifle from one of the many offerings currently available. That could include what PWS is now offering. There's also LWRC (which I now own), Ruger, S&W, Daniel Defense, LMT, etc. to name a few current from-the-ground-up piston designs.
I often wonder what the LWRC would have been like, The one I had on order for almost 2 years. And then there was the P.O.F. that was on order for about a year. Both guns would have been a little over 2 grand. I got sick of waiting and got hip to conversions, the main ones being PWS and Adams Arms. I thought the AA looked promising, so thats where I went. No permanent conversions and I could spec everything I wanted. Anywho The AA has been great, no problems at all. I have never had any problems in the gun. Nothing has ever come loose and it has performed admirably.
But ever since PWS came out with the dedicated line, I have been in love with the MK114. I currently only own one product from PWS...the FSC556 comp/flash suppressor. I love it, and the company seems to be very inventive.
Once someone sees the deal offered in My Sabre Defense Adams Arms build I'm selling, I will probably roll the money into the MK114!
i rock a pws piston system in my addax upper. its pretty smooth. basically turns the ar in to a ak. this is my second one. my first one i shot probably 15k through with out a single problem and nothing more than wiping it down and running a bore snake through it. the mk114 is basically what i have before they started really doing their thing. either way i haven't had a single problem and would say go for it
on a side note i also have a pof and lwrc and both are also great guns. i would give the nod to pof and lwrc for accuracy but only slightly. i think it has to do with their barrels. i think with any you will be good to go and they will do all you want