As an addendum...

If'n y'all can't tell, there is a fair amount of bad blood between the two.

One of the fundemental differences will always be: SCA: Hobby done almost entirely for self, aimed mostly within, without taking theatric nature into account

Renfaire: Theatric event with historic elements, of varying authenticity and intensity. Largely concerned with audience interaction and happiness, as they are all businesses of one form or another.

Both are hobbies. Somehow, I wound up in the one that makes other people money...

M