The Big M4 Myth: “Fouling caused by the direct impingement gas system makes the M4/M4A1 Carbine unreliable.”
Cleaning Your AR-15 is Pretty Much a Waste of Time | Vuurwapen Blog
A piston AR will have just as much if not more problems due to additional moving parts. A properly staked gas key, like a properly staked castle nut, will hold till the next maintenance schedule and beyond.
Still a good thing to add, checking gas key to the AR's PMCS.
An option to mitigate carrier tilt in piston ARs is this:
Firearm Ready Solutions
I love simple and ingenious solutions, especially if its by one of the little guys, so, since I was going to get a flat wire buffer spring anyways, I went ahead and bought one of these for my DI AR.
Tight bolt lock, no BCG bounce, smooth cycling and I don't hear the "sproiiiiing" on every shot. Ok, maybe the smooth cycling is just all in my head.