I have a PWS MK 2 SBR. I changed some things in the buffer and shoot it exclusively with a can. It is my most pleasant SBR to shoot, in no way is it the most reliable. I think that two of my DI rifles are more dependable.If you're looking for pure reliability on a budget, I think the PWS MK PRO is probably more reliable than any DI gun including KAC, Geissele, etc just by the basis of it's design and function. Especially if you run suppressed with a lot of gas/stuff coming back into the receiver.