I use it on iPad. It is amazing. I use it mainly to add drum fills to the basic drummer track on my songs in Garageband, and to add touch instrument tracks (eg: piano, organ, synth, strings, vibraphone, electric piano etc etc). It really does work well.
It's free, try it out. You can use it for remote control of Logic Pro, and you can use it to play virtual instruments which may be useful, but definitely fun.