I have an Arak21 and like it. I've only gotten to shoot it once due to limits on my time and finding a decent place to put it through its paces. It's heavier than an AR15, but that didn't phase me. I had zero malfunctions.
As for an SBR, the only thing I would say is that because of how the gas adjustment knob is set up, you probably can't go any shorter than the factory 12" barrel. You need at least that much space to get the knob out, and any shorter I think the muzzle device, probably ANY muzzle device, would block it. I could be wrong, maybe Faxon can advise?
So as long as you're OK with that, yeah, go for it. I have not shot a short one yet, haven't gotten around to my stamp. When I do it'll be for a suppressor host, I don't see myself shooting it without one.
Also I'm right handed and can't help with the LHE function. Good luck.