Anyone know anything about disc brakes?

Seriously don't bother, it's an endless pursuit of attempting to polish the turd of brake that they are, at least with my SRAM apex levers. Even when I had them setup well it would only be days before they were noisy/juddering/ineffective again.

Hmmm. That's depressing reading. The bike I'm looking at comes with SRAM Rival levers. Noisy/juddering/ineffective doesn't sound like the most enjoyable new-bike experience.