This is one of the best music apps on iPad. – Midiflow Review

I have yet to find another piece of software OR hardware that can do what this app does - and it does it so intuitively! This is one of those apps that, if you have a hybrid software/hardware setup, is worth the price of buying an iPad alone. In addition to all of its MIDI routing capabilities, it breathes new life into software and hardware synths that have limited MIDI specs - allowing you to, for example, use after touch to control something that a synth natively can only map mod wheel to. Etc. I have bought every IAP and will buy more if they are released, although I haven't yet found anything that this app can't do with regards to MIDI.
Review by pepperdancepapa on Midiflow.