When I saw the screen shots for this it struck me as looking a lot like Auxy, and yet this app costs $19.99. Not sure why though.
Here are the details, you make up your own mind.
Mizu Pro offers a complete music production environment. It allows you to create and save complete multi-track projects on your iPhone or iPad. Put a whole music studio into your pocket and you will never lose any idea while you’re away from your computer!
POWERFUL SOUND ENGINE
Create music in the same audio quality as a professional studio software;
HUGE SAMPLE LIBRARY
Thoroughly selected music samples by professional musicians;
Add as much instruments as you need for your track;
Compose a lead melody, strings, bass, and drum beat. Adjust tone and duration of a sample;
Combine all your loops into a whole song
SAVING AND EXPORT
Save your project on your device and download it via iTunes file sharing
Mizu Pro on the app store costs $19.99 (maybe try Auxy though)