In all honesty, the only complaint I have with SOL Republic is consistency. To elaborate, when I got a functional pair with no defects, it worked great. I even threw the "engines" against the wall as a stress test and there were barely any scratches to show for my efforts. However, I've gotten defective pairs multiple times. A common defect is that the engines can be "twisted." If you grab the the padded end and the other end and twist lightly, the engine would twist with your motion. I'm not sure how to describe it, but to this date I've gotten three defective engines with this same problem. I've talked to a lot of others with this problem as well, so it seems fairly common. It causes loss in volume and a kind of a rattling sound would appear while I was listening to music.
The upside is that the customer service is pretty great, and they'll usually send you a new set straight away.
I agree that SOL is on par with m80, but as to consistency and build quality, they aren't quite there yet. But then again, they are a relatively new company.
On another note, an over ear design has been released at CES. Its called the "Master Tracks." Looks promising.