I'm not a booster expert, but I would certainly vote for sending my booster to Booster Dewey for rebuild rather than trying to track one down at a part store or other source.
My former employer owned the Raybestos name for brake parts and were Napa's source for the United brake parts, In other words, they are both the same part regardless of what the box says.
I got laid off in 2005 and by the end of that year they had pretty much shut down all North American manufacturing. I can certainly vouch for the quality of the product when it was made here. Now all brake manufacturers pretty much source everything from the other side of the Pacific, and I believe all brands on the market source their parts from the same manufacturers. Therefore you might as well just shop for the best price you can find and don't consider the name on the box to be very relevant.
I don't trust Chinese parts as far as I can spit, the current situation sucks but what are you going to do when the only part available for your car is made there??
Personally I have been keeping my eye out for NOS and NORS parts and trying to stash some parts away for when I need some in the future, so I won't have to put questionable Chinese parts on my cars.