I will give a very hearty +1,000,000 for the Avid BB7 setup. For long out of the way cross country rides, cable brakes are the best IMHO. If you have brake problems, restringing a cable as compared to having to bleed out a brake line is much easier.
Definitely not going to argue this point - there's a lot to say about a purely mechanical system in the middle of nowhere - but, in thousands of miles bikepacking, I've never had a problem with my Shimano XT hydraulics. Love them.