I use the 12" version, the ex112 with a GK MB200 for both home practice and for jazz gigs with my upright.
It is very "middle of the road" as far as efficiency, neither good nor bad. However, the coax speaker gives a nice smooth and balanced high end without the abrasiveness of a tweeter. I don't like my tone super-snappy regardless, but it sounds nice and balanced and natural to me.
I would NOT attempt to use these cabs for a higher volume gig, even in pairs. They just aren't going to handle the pressure. The driver is definitely not designed to be robust, but rather to sound sweeter at lower volume uses.
The box itself is built like a tank, quite heavy for its size. FYI, I replaced the 1/4" jack on mine with a single speakon and it took minutes, well worth the effort.
Consume media wisely..........