Just to add to the choices, I picked up a Dokata Tactical MP5 clone on the used market a couple of years ago. True Roller Lock clone. Made in Michigan I think.
It has been flawless, even when absolutely filthy.

I've got two Zeniths, full-size and a PDW. Both have been utterly reliable and a blast to shoot. Both have been shot at least 50% suppressed. A coworker has a PTR and it seems very well made and ran well.

Might also consider Omega via Atlantic Tactical.