GarageBand For iOS continues to impress as it becomes more sophisticated; and while you likely won’t finish a full production with this app, it’s becoming an increasingly good sketchpad — especially with the increased Logic interoperability.
Steinberg update Cubasis 2 with real-time time-stretching and a “carefully redesigned user interface”, which amounts to a flatter, cleaner design that’s a little crisper and more pleasing to the eye than previous versions.
FL Studio has always been popular with those seeking a cost-effective, easy-to-use alternative to the 'big name' sequencers. The latest version adds a new drum sequencing tool, high-quality time-stretching and video support.