I have an SBR that I pieced together with quality parts and I also have a suppressor for it. I have "zero" experience with the (.223) clones, except the 53 and 53K I have handled in person that Ghillie built for a local buddy of mine, outstanding fit and finish.
You mentioned something about primary defense use. "For me", the decision was simple, I have a good amount of training behind an AR type weapon, so that's the route I went. Parts for them are "everywhere" and relatively cheap especially in comparison to genuine HK parts for anything. I have a 12.5" barrel (wanted an 11"rail for comfort), and an AAC M42000. It's not quiet like a suppressed 45 pistol, but it quiets the gun down significantly, and with the can on the rifle barely measures over 16". When the can is off, as far as noise goes, I really don't care, it does not bother me. I have an AAC brakeout mount on it and have shot it at night without the can and no issues with the flash, sound, etc. It's loud, but it only bothers the people around me
When I go to train, if my rifle bugs someone, then maybe they should have sat down and thought about how much noise bothers them before taking a class with 20+ people shooting rifles. I live in a big city area, so the added distance folks talk about with the longer barrels is a moot point to me. I have a short barreled AR with an Aimpoint 4MOA on it, and it fits "my" needs perfectly. When I set out to build this rifle, it wasn't for it to be a toy, it was to be a tool that will get used and abused, and after swapping/upgrading a few things along the way I'm happy with where it's at.
Now this is not to say that a 93 could not be used in the same role, I just think familiarity of arms with the platform makes it or breaks it. We have a guy locally at the carbine shoots that's always coming out with his 53K build, so it can be done.
Good luck and let us know what you decide.