Well, the fastest method is the one that uses the fewest moves. It's the one that use a reasonable amount of moves and less pausing between the moves. Most of cuber's time is wasted looking for pieces if you use a method like Heise, which is one of the methods that is used in fewest moves and isn't great for speedcubing because it require great amount of memory to tracking nearly all pieces.
So Heise is best..but it is much harder and takes more practice. Full circle eh?