There are some great sounds on this, but... – VOLT Synth Review

The compatibility with anything moderately substantial (longer than a minute) done in GarageBand will crash the audio on the Volt Synth. This then requires the entire project to be closed out and GarageBand to be rebooted and maybe, hopefully, your Volt Synth audio track will have sound again. Otherwise, record it in standalone mode to an external recorder. But this doesn’t work for people stuck traveling around away from their gear who use mobile DAWs.
Review by lofidelityrockr on VOLT Synth.