use both of them. Sometimes small ball is the best approach for the table, for example, in huge field events with loads of fish. Being in loads of pots and extracting small value trying to catch someone in moderately big pots with second best hands.
other times its best to just play power poker, on tough tables where you have less skill edge or no skill edge postflop, or in turbo structures.
So i would say both are applicable at all times, it just depends what you can do or get away with. Obviously having a standard way to play is great, which might be a small ball type style, however you should be able to change and play power poker if you need to as well. For me it all depends again, on the table and opponants and strucutre of the tournament.