Drambo

I would give this app ten stars if that would be possible. And it's difficult to put this app into a specific category because it is so versatile:

• The Drambo UI and the way how the patching and connecting works are perfect for touchscreens - even smaller iPads. A pleasure to work with. No microscopic knobs or dangling virtual wires.
• Clear sound. One can build great sounding synths, drums and effects just with the built in modules.
• I play mostly hardware synthesizers, and Drambo is great for sequencing external gear.
• The app is worth every penny you pay for it. So are the IAPs.

In two words: Well done.