Cable discs will have the same maintenance requirements we V's as the cables stretch/break etc. I've had hydraulics for almost 10 years, since Hayes and Magura first started production. I've since moved into Shimano dual controls and through it all I've never had to do maintenance and the initial setup was not as hard as I've seen it portrayed.

To me the biggest difference is the feel. No cable stretch, just a real positive action with the hydraulics. And on longer rides it definitely makes a difference as your hands fatigue.