Difference between various piston systems?

[Droppin Deuces]

Does anyone here have a good enough understanding/enough experience with different piston systems to give an informed recommendation when someone asks? I'm not trying to start a debate. Or maybe I am! I just want to know so that if I do ever buy another piston upper I'll have a better idea as to which I should look at. I'm always hearing that so and so is the best, don't even bother looking at anything else, etc., etc. But no one ever really explains why that is.

[Jonathan Doe]

I believe they are somewhat similar, but was told that LMT system is a little better than other ones. Never had one, and really do not care for the gas piston system.