I don't have any suppressors (although I would love to have one or two), but one thing I know, is that they get dirty with use like the rest of the gun. If I was going to get one soon, I'd be making sure I got one that can be disassembled for cleaning (some come apart quickly and easily and some don't). Generally speaking, the longer ones are quieter than the short ones. A friend of mine has two, and boy, they really quiet a rifle down to more of a .22LR kind of report. With a modular suppressor, you can adjust the length and (I think) in some cases, caliber application.