This is nearly the greatest practice app ever made. I bought the desktop version. Move over Jamey Aebersold, at least a little bit (cant beat the real thing, especially if its Ron Carter or someone). But for $20, this is a steal! The flexibilty of it is incredible - change the tempo, key, time signature, yeah thats basic stuff, but the ability to change to so many different styles and then customize each is fantastic. The mixer is key (although I wish there was a guitar comping option), but pull the bass back and practice your bass solos. The comping is great too, its not the same rhythm each bar and they have some formula to randomize it, I guess, its really neat. Creating your own song is a bit clunky. The editing window is kind of narrow, until your Save and it goes to half screen size. The input of chords is simple (although you have to follow their guidelines - D-7, not Dm7, or D-7b5 not D-7(b5)). But inputing them will get easier and be quick, Im sure. I will wish you could type the tempo in, instead of have to use the slider in 5 bpm increments. I cant wait to try the MIDI export options into my DAW and other features, how about the thousands of other songs in the forums?, but after 10 minutes, Im blown away! Get it.