A friend of mine who is a keen mountain biker bought a newer version of the bike he had which included some fancy disc brakes. He swears if he buys a new bike he will go back to V-brakes. Apparently lining them up is a hassle and tinkering with them is a bit more difficult and there are some other problems.
However, as a casual biker i thought the disc brakes I had on my MTB at home were epic! But then I wasn't overly bothered by the high performance of my bike, more just the fun I almost flew over the handlebars the first time I used them as I wasn't expecting them to be quite so powerful