I was playing around with Sketcbook Express by Autodesk and it was a little lfun.
But I found it hard to control the file size - well not that hard it's just easier in Photoshop .
The pecil tool worke dpretty well but the tools in Photoshop are better. I think maybe that Sketchbook express is goo if you're sketching on a tablet or ipad and you're on a bus or in a museum with no keyboard.
I'm still a photoshop fan . this is just a qick sketch drawing as if I were drawing on toned paper with charcoal pencil and white conte`. Ten or fifteen minutes on this one.