Very cool! I'm a n00b to the music-notation-app-world, but was able to get going pretty quickly. I'm not sure if any of these are already standard features on most music notation apps...but I think keyboard shortcuts to the note/rest types would help. Maybe even an option to eliminate some clicks (just press the key corresponding to the note/rest to place it underneath current cursor position)

Then again, being a n00b, maybe I don't realize that speed-of-input isn't the bottleneck for composers hehe.