Hmmm, I like the look of the avids (the 6 especially), but all the reviews I've read have said they're a nightmare for squealing. But then again an equal number of people say the same thing about the Tektro Oryxs. The Tektro CR520/CR570s (with an upgrade to swiss stop pads) seem like they might be an alternative...
https://www.lfgss.com/thread48501.html#post1597391