I have a brand new Amal for my BSA. It's on the shelf. I went with the Keihin-style PWK and never looked back, though the "purists" look down at us conversion types.
The Amal is NOT a bad carb. The problems with the Amal Concentric is two fold. One, once the pilot circuit clogs at that 90' turn in the body casting, it's almost impossible to get in there to clean it out without drilling. Secondly, the pilot circuit is fixed, not jetted. If it's not quite correct for your application (engine size, mods, etc.), that's the way it's going to live, unless you get one of the new (and expensive) modified versions of the Concentric, whether it's a 928/930/932, etc.....
I completely understand wanting to stay original, like my BSA, but for riding, I'll keep the originality on the shelf for later use.