CraigFPG received an evaluation Mattebox unit from Cinetech and posted his thoughts on REDUSER.

-The swing away hinge seems pretty sturdy and locks in to position. Not
wobbly as seen in the freshdv review of their hdv mb.
-No vertical adjustment I could find. There is horizontal and it fits fine on
the RED 18-50mm zoom.
-The rubber bellows/step down has a machined aluminum ring that acts
as a collar around the lens.
-The other end of the rubber bellows is also machined aluminum and it fits
inside the matte box which has six pressure sensitive ball bearings on each side that
keeps it pretty snug.
-Those bearings allow the first stage to rotate. As you rotate it the entire
rubber bellows rotates, including the ring against the lens housing.
Potential for metal to metal scratching.
-The three front trays slide in from the side and are held in place by
friction and what looks like spring or pressure points in the mb frame.
There are no set screws to hold the trays in place. I don't have my filters
yet so didn't have a chance to try any to see how well the really hold.
-Don't see any mounts for a french or side flags, I am going to call
tomorrow to see if they are available.