FarHorizon, you are correct in that disc brakes are the tops. Discs offer better modulation, work much better in wet and muddy conditions, and do not wear the rim as will canti's or V's. For riding where it isn't too wet or muddy, a quality set of V's are plenty and definitely more powerful than canti's. I guess it depends on the V's also-really like my Avid's, have worked on bikes with Tektro's that didn't seem that much better that a good set of canti's.
If you ask me if discs were a worthy upgrade over V's, I have said yes to that also. If I were racing, or rode a lot in wet or muddy conditions, I'd have discs (most likely Avid mechs-seem less problem prone than hydraulic).