Small pneumatics to fire in poor vis and close range are easily dominant. You can load them way faster and they cut through the water like a knife. Sure they can be very top heavy if you don't have the proper length setup. I have shot over a 2000lbs of fish my with 70cm cyrano. I haven't even opened it up to do any maintenance. I can reload and shoot up to 3 times in one breathhold.
Pneumatics still have less recoil than bandguns.. All railguns, riffe, Wongs, SeaSniper...to name a few
The mamba kits make the pneumatics more powerful than a standard 2 banded gun. As you can see in my videos, the shots are pretty impressive. My gun 115 asso with mamba kit is also perfectly balanced. Its not top heavy at all.
But in the end, it really doesn't matter what you use. Use what gives you the best results!
I was going to post that too Sporasrub. 