iPad Drawing App

I downloaded Sketchbook Pro on my iPad quite some time ago, and used it in a life drawing studio for a few long poses. Only recently I tried casually sketching with it. This is a sketch of my dog, Ditto, a 6-year-old Boxer, as he snoozed. Drawing on the iPad takes a little getting used to, but hardest of all for me, is finding the right tool you want to use. This sketch was done with a dry brush at its default setting, using a Bamboo pen -- the kind with the big rubber tip. I've since purchased a few finer point pens that are much more natural to work with and flow more freely on the glass surface. Although, I have to admit, I do miss the pleasing feel of pen on paper. And why, with almost unlimited levels of undo and onion-skin tracing, do I feel like I'm cheating? I haven't used the tracing abilities yet, but the undos -- I'm at expert at using those.