Remanufactured Carbs

Hi all. I am looking for a 2bbl slant 6 carb, and while researching and shopping, I keep reading that reman carbs are no good, but there is never an explanation as to why. What makes them bad? It doesn't seem like there would be any market for them if they were all as bad as they are made out to be. Did someone once have a bad experience and said that reman carbs are terrible, and then everyone else jumped on it, or is that really the case? (I know to stay away from Chinese!) Just looking for some feed back from the group while I'm still shopping!
I've never bought a new carburetor in my life! Both my carburetors on my dual quads are freebies from Chevy guys who don't know how work on carburetors...
Is there not a rebuild kit for the one you have?