In reply to LastBoyScout:
> Hydraulic are more powerful and have more "feel", but are a fiddle to maintain in comparison
I had some older cable discs on my Kona MTB (bought about 7 years back), they were OKish but never that good then seized up after a winter (snow, ice, grit and salt where I live) never to unseize. I replaced them with some Hayes 9 hydraulics which have been fantastic ever since (maybe 5 yrs now).
When I got a new hybrid as a commuter about 5 years ago it came with shimano hydraulics. They were fantastic. I think I needed to bleed them once, and change the pads once in something like 10,000 kms of commuting. And they were cheaper end of the scale. Really reassuring when riding in busy traffic, especially in winter.
I recently bought a CXer to replace that, it came with Avid BB5 cable discs. I've got them working pretty well now, but I think they are much more fiddly to deal with than the hydraulics. I love my new CXer dearly (went past 500 kms on it earlier today!) but the brakes are the one thing I miss from my old hybrid.
I think cable discs have an inherent weakness as only one side of the brake moves against the disc, whilst on hydraulics the pads are compressed equally. Fiddling about with inside, fixed pad seems a bit of a fiddle but needs to be done very carefully to get the best performance out of them. Roll on hydraulics that can be used from drop bars, preferably with a second brake lever on the flats!