Hanging turrets seem like a rather interesting bit of engineering.
Yeah, I do wonder how they would be mounted and dismounted for overhaul, but I suppose that having a world with antigravity based lift gives you a blank check for improbable engineering.
Well, with antigrav tech, mounting and dismounting should be easy. Fastening them in place, moving them, and keeping the ammo moving smoothly would be an interesting exercise in ergonomics.