I recently bought a Cube, and it took me about 1 day to replace the clamp with a RRS screw clamp. Now works much better !
The Cube adjustments are very very stiff out of the box, but it is slowly becomming better. I'm told it will loosen up with use and be smooth to operate.
Works very well as a leveling base when using a long lens also. (I have arca-plate on the bottom of my gimbal head, and in fact on the Cube also).
If anyone's interested, will post some pics of the overall setup.
Regards
Mark.