Lots of topics on this one, but my opinion is that it's a copout and that if you want to play double bass fast then build your footspeed and don't cheat with a triple. Unless you're Thomas Lang, he actually uses them for a good reason.
I think its abit of a cheater pedal tbh, Its always best to learn the hard way. 4 limb independence is important as a drummer. Getting the foot you use the least is a really good thing to practice, it makes you a more flexible drummer and more rounded. Dont get a dualist because in the end its not going to do you alot of good as a drummer, unless your an absolute wizzard already then just ignore me
I have always drempt of getting a quadruple bass drum beat goin with 2 of these pedals on 2 bass drums, because it would be just freaking incredible, but it's true. It is a cheater pedal. but i still woudnt mind takin it for a test drive, though.