This app is a Swiss Army knife. I cannot tell here the many many times I was able to route audio and/or midi in the craziest of ways so as to either work around DAW limitations or to process audio in very specific ways.
This software is the single best acquisition to my music arsenal this past decade. Period.
And if you're a programmer, you can create your own "Bidules" to perform very specific tasks. Once I posted a specific need I had in their forum and one of the developers himself offered me a mathematical equation that controlled the feature I was looking for. That way, I could manipulate the speed the way I wanted.
(BTW , their customer support is beyond awesome.)
Perhaps Max/MSP has more features overall, but Plogue Bidule does everything a musician needs for a fraction of the cost.