I've linked this thread to a number of other threads covering the "worst" of whatever in music. I don't know exactly how you'd describe this classification. If it's the "best," then it's a superlative. If it's the "worst," is it still a superlative - or is it a negative superlative.
Anyhow, I've found in my nearly 14 years at Mudcat, that threads on superlatives don't usually work very well, since it's all mostly a matter of pure opinion, not information. So, then they end up being squabbles.
That being said, I have to say that I don't really listen to Leadbelly or Robert Johnson for pleasure, although I agree that they made significant contributions to folk music. But their recordings grate my ears, as do most old recordings. Recordings did not become listenable until the 1940s, and even then sound quality often left much to be desired.
-Joe-