Back in the early spring I put SRAM Pitstop Flak Jacket Cable Housing on my cross bike. I liked how well it worked on the Avid road BB7 cable discs on my cx bike that I put it on my mountain bike too.
After months of use on my cross and mountain bikes, both with Avid BB7 disc brakes, I can say these things rock.
The cables are high quality with minimal compression and have ferruls that have rubber seals and protrude through the cable stop about an inch to fit a plastic cover over. This is what keeps all the mud and water out.
Not only do I ride in mud and rain, but I wash my bike with a hose after almost every ride. I am not miss shifting or getting that hard-to-push-the-shifter cable drag feel you get with normal cables and housing after moisture/mud gets in.
They cost a bit more than regular cables, but they will pay for themselves since you can leave them on much longer.
Totally worth it.
-Joe
This cable housing sounds rad.:)