This largely depends on how you ride and how much work you’re prepared to do to look after your bike. Cable-operated disc brakes offer better progression and feel than older-style caliper brakes, but hydraulic is another step up again. If you’re looking to maximize control in all conditions, hydraulic is the way to go. However, these brakes are more complex. If something gets damaged, they’re more expensive to repair. If you ride for leisure, cable is probably sufficient. If you ride with a group that gets competitive, choose hydraulic.