93 and 33 are the same except for full auto capability. They are the way to go, if you plan on shooting well past 200m. The 53 is much better for closer targets and CQB type scenarios. All are the same functionally. In full auto, you get a big muzzle flash and loud noise from the 53 though, due to it's shorter barrel. Great fun for you, but not so much the other guys in your stack or in the lanes on either side of you at the range. I've actually had people move lanes on me and complain to the range officer.