Problem areas:

Supercats are usually bulletproof, but sometimes there are issues.

Older SC20s had an issue with the bow tangs pulling out. That was fixed, but I have heard of a few that had the failure. I think there is an article about it on Aquarius' site. If not, ask and someone could tell you about it.

I have never seen one that has delaminated! If yours has delamination, it means it was really abused and neglected.

I have heard a lot of horror stories about the sterns getting ripped off the boats. The SC steering is really nice and it locks down (and releases well) but sometimes people have them over tightened and they don't flip up when needed. It isn't a factor of poor engineering, it is a factor of poor rigging (IMHO).

The biggest problem with a SC20 is finding the stones to sail the thing. When it is blowing and you are screaming along, it sounds like a freight train and the spray coming off the bows is like a fire hose.