What are some alternatives?
NanoStudio - NanoStudio is a recording studio for iOS, OS X and Windows.
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.
AudioKit Synth One - Free & Open-source iPhone/iPad Synth 🎹
OpenMPT - OpenMPT is a popular tracker software for Windows.
Sampulator - Make (and record) beats on your keyboard
Renoise - Renoise is a digital audio workstation.