I use this App with Ableton Live. It works okay. There is some latency. The documentation is weak, which is bad for configuring the App because the interface is not intuitive, at least to me. Its a one trick pony, a matrix of triggering buttons. I have only one iPhone, so I really wish the developer would consolidate all of the stand-alone apps into one fully implemented App (i.e., the developers existing intro-App, ITM MidiLab). A fully implemented, well documented MidiLab suite would be worth $5.99. Standing alone, with latency and poor documentation, this ITM Matrix App is worth no more than $0.99.
Carmen Scriptor about iTM Matrix