BeatMaker 2 (and in fact BeatMaker in general) was one of the first music making apps on iOS. In fact I think the original BeatMaker was in development even before the SDK. It’s an excellent app and is so full potential. BeatMaker keeps developing too, moving forward and adding new features.
I’ve no idea what they’re up to for their next release, but whatever it is, I’m sure it’ll be worth waiting for.