Ready to run distributor thoughts?

I've had two cars that came with "ready-to-run" distributors on them.
They weren't Speedmasters or MSDs, but they had the "red cap" on them... :rolleyes:
Never could get either one to run right, I finally put factory stuff back on them, and voila- ran perfect.
I know some people say they have run these with good results, but to me, cheap ignitions are just asking for issues, even if they work fine initially. Think about parts availability down the road- if you'll even be able to get replacement rotors and caps, let alone pick up modules. Just finding diagnostic specs can be an issue.