The only thing I'm not too keen on with the DrBass 310 cabs is they have kind of a funky 2+1 wiring to achieve 4 and 8 ohms with 3 drivers. They do not use 12/24 ohm drivers.
For example, for 8 ohms, it's 2 8 ohm 10's in series (for 16 overall) wired in parallel with another single 16 ohm 10 for (16' || 16) = 8. This means one 10 is getting twice the power of the other two, which bugs me a bit. They say you can't really tell from an audibility standpoint, but even if that's the case, just knowing the power is so unevenly distributed inside is a bit unsettling for me. I'd be worried about that lone 10 under heavy power such as approaching their rated 750W each... that one 10 is getting 375W of power in that case.
I'm guessing they need to rate it based on what that one speaker would see in a given situation, apparently a 250W, so the cab should probably really be rated at 500W, not 750W max, and the fact that the other two drivers will never be pushed hard is moot.
Other than that, they look like cool cabs.