I've been riding my Genius RC Ltd for 2 years now and it's one of the sweetest bikes around. Despite my exceeding the recommended weight limit by a good couple of kg's (no, I won't say how many), this bike has been an absolute dream.
Full cable outer is the way to go. I have been running my cables on a Scott Genius RC ltd like that for 2 years now with no hassles at all. The problem with using your water bottle to wash your cables en route is that this tends to get more grit stuck to them. Exposed cable is the devil, and even more so exposed cable running under the BB. What bright spark came up with that idea?