To answer the OP's question, if by control you mean stopping power, which is normally the big scare when at some point it turns out not to be there, then discs are best. But discs are heavy, sometimes affect wheel integrity, racks, parts, and durability. They are also increasingly being added to bikes, but are currently not standard on most touring bikes sold here. I think that will probably change. XC will probably send some changes out way soon enough.
I don't live in the Rockies, but it is otherwise hilly in an Appalachian way. Around here cantis are my favourite and give me everything I need. I think cantis are the best brake relative to virtually everything other than stopping power. Their real breaking power with road levers is similar to what you can get for V brakes, and they are simple, light, easy to maintain, keep working if a wheel is out of true, etc... Some of them with really grab a wheel, like the Petersens.