The best to say about ThumbJam is that it made me curious to explore the world of music on the iPad – and that it stayed among my top apps ever since. The number and quality of sampled instruments included is impressive. More instruments can be downloaded for free. The variety of scales is a cultural journey around the globe.
It should be mentioned that ThumbJam does a superbe job to take the gyroscope and accelerometer as input to twist and bend the sounds, e.g. shake the iPhone to play a wild e-guitar vibrato.
Update: I even found an easter egg – on Easter!!