I am the type of guy that will give Chinesium a chance if it won't destroy anything in the process. I have one of those eBay HEI distributors on my Bonneville and my El Camino. The ones I received had nice machining and decent quality cap and rotors installed. Shaft endplay was good, and they both came with adjustible vacuum advance cans.
I haven't had any issues with either one, other than one of the ignition modules was a little grumpy when it is below freezing. A quick swap with my old distributor seemed to cure that issue.
Overall not perfect, but $50 for a complete working distributor makes it well worth it to me.