I have a love/hate thing with piston driven guns, but Patriot Ordinance Factory's design is very simple and super reliable. They stay much cleaner at the receiver vs a gasser, but its more stuff to keep up with for sure and the op-rod hitting the BCG has a bit more pulse to it. They do weigh more. The coolest thing about them is the NP3 coatings make it cycle smooth as glass. I'm skeptical of any coatings but that stuff wears like iron. I literally saw no wear on it till I got past 10K rds through it. I run em wet too so Im sure that helped. Ultralight Mobil 1 oil

My best friend and shooting partner has 2 BCM's that have been really solid guns. He had an early one that did have an ammo malfunction and a squib lodged in the barrel right in front of the chamber and the gun literally blew up and cracked the chamber when the next round was fired. He was doing gun/run stuff at the time and it all happened so fast he shot again before he realized there was an issue.
It would have happened no matter what gun was being used, but BCM sent him a brand new gun free of charge. Cant beat that.
Thats great customer service. Zero problems with the 2 he has now, he loves those things.
There's a ton of good stuff out there at the moment, prices are still up a bit but the selection is fantastic. You have the skills and the tools to build your own, your way ahead of the game