I HATE internal cabling.
I understand the reasoning, if you are competing at the highest level every little iota of aero advantage counts. But for the remaining 99.9999 recurring percent of us it is just one big pain in the ar$se. Changing a shifter cable is one of the most common maintenance tasks on a bike, and also the easiest - or it would be if you didn't have to spend half a week trying to thread it through the tube and out the other end.