I was very tempted by many of the ALLSTAR accessories but always found something that suited my needs just a bit better from other vendors. That said, you will not find better customer support than WC, and while their products are far from cheap, they are less expensive than some and extremely well made.
My only concern regarding the WC bridge plate I posted about in this thread that (so far) no one has replied to. If you use a 19mm rail support bracket for a matte box, be aware that it MAY snag on the front of the dovetail plate when you mount/dismount the camera. After reworking some parts on my bracket, I was able to get it to where it only snags on the small screws that serve as safety stops on the new WC safety dovetail plate (the one that ships with the handheld rig). I'm still pursuing alternatives to having to screw/unscrew that screw when mounting the camera, and I'm not even certain that WC's plate poses a unique problem in this area. Could be that every other Arri style base plate would do the same thing. But it could also be that the ports on the baseplate for the 19mm rails should have been placed slightly higher vis-a-vis the level of the top of the dovetail slot on the baseplate so that there is greater clearance of the rails themselves over the dovetail plate. I'm not talking about the distance between rail centers and optical center on the camera, which must be 120mm to be standard, but about distance from rail centers to, essentially, the level of the baseplate that comes in contact with the dovetail plate.
I also would prefer a positive "snap" on the lever that locks the baseplate to the dovetail plate, but once you engage that thing, it's not going to come loose without purposive movement, so this is a minor complaint.