What are some alternatives?
When comparing SunVox and KORG Gadget, you can also consider the following products
MilkyTracker - MilkyTracker is an open source, multi-platform music application for creating .MOD and .
DRC - Polyphonic Synthesizer - Cross-platform, virtual synthesizer for iOS that recreates the sound of classic, analog synths.
Renoise - Renoise is a digital audio workstation.
Caustic - Caustic is a music creation tool inspired by rack-mount synthesizers / samplers rigs.
FL Studio - Image-Line's FL Studio, now on it's 12th version, is a well-known music production suite and the most popular beat processor on the market, due no doubt to its longevity. Read more about FL Studio.
Poison-202 - Vintage MIDI synthesizer for Mac and iOS