Cube works great on 4x5, just like with any other camera. Big advantage to any geared head over a single-lock ballhead is the ability to level the roll axis separate from the pitch axis, separate from yaw. However, the B2 is not single-lock, so you can adjust pitch and roll and yaw separately, and it was my preferred head for my big format cameras too. Only advantage the Cube has here is for smaller cameras, the geared movement and then total weight, as the B2 is about 2x the weight and not geared, but definitely more rigid when locked up. (I think you can park your car on a B2 and not hurt it.)
FWIW, I found the Cube was too small for my 8x10 camera and why I used the bigger Arca B2. IMO the Cube is good for up to 5x7, or maybe a Phillips 8x10, but not the real big boys.