I used Centric brake/clutch masters, never had a bad one yet, but their wheel cylinders don't appear to all be the same even though they are in a box with the same part number, so now i always open them and look at them in front of the parts guy at the counter, if they are not like my sample or both the same I send him back to look for another one.
I will not buy anything other than Centric anymore on brake masters, all the other brands do not work out of the box, I bought one that was put together wrong, took it back and they were not happy at that parts store.
^ That. I work as a tech...if I'm buying aftermarket brake parts, it's centric. Nothing out there short of factory is any good. This goes for clutch master/slaves, brake masters, calipers, wheel cylinders. I even like their brake pad kits too.
Companies like raybestos bank on old timers still having trust in their products. They used to be good. They are all cheap Chinese crap with a crap-roll whether you got a good one or not.
You really want to take that kind of risk with brake parts?
Not me. Not for my cars. Not for my customers either.