It may lack the "soul" of sketching on paper, but I sure don't miss all the clean-up!
What initially turned it around for me was the game Draw Something. I enjoyed playing it so much that I began to feel guilty for sending people these elaborate scenes with detail and composition and color blocking, when all they really need (or want) is a concept elaborated with just a few quick stick figure brush strokes.
The next turning point came when I bought a stylus that I liked. Because although I'm surprised at how well I can make art by drawing with my fingertip, I still craved the familiar feel of a pen in hand.
IPad + stylus + Sketchbook Pro = WOW.
Drawing on the iPad with Sketchbook Pro makes me realize how much of creating art is the drudgery of setting up your tools, and cleaning up afterward. My favorite medium is to sketch an outline in pencil, ink in the lines with a dip pen, then add color with watercolor. You have to wait for the ink to dry (twice!), clean the dip pen while trying not to spill ink all over your desk, set out the little tray of watercolors, mix the paints, try not to spill the paint, keep refilling your rinse cup, wash out the little trays when you're done…
Or you can just tap a few points on your iPad screen. DONE.
Using the layers in Sketchbook Pro lets you recreate the experience of sketching, inking, then erasing the pencil marks - without any mess, fuss, or accidentally lifting up your ink. You can add infinite color, and there's an "undo" button. Want to experiment with some oil painting techniques? You can do that, just choose a different brush option and transparency levels.
Making art on the iPad does feel like some of the "soul" of the process is lost. I miss the smell of paint, the tactile feel of the dip pen scratching against the paper. But I sure don't miss having to wrangle and clean all my supplies.