I'm no Jim Lee, but darnet, I am an artist and we have Sketchbook Pro too! It was the whole reason I wanted the silly iPad in the first place. So I decided to break it out and "get serious." My first attempt is a bit clunky and it's going to take a little getting used to drawing with my finger (I plan to get a stylus soon) but it's so much fun!
I love the splatter brush and I think it was a fun brush to play with to get started and just do a loose illustration. I went into it thinking I was going to do a perfect illustration but found that just playing around was fun and the outcome was still neat, if not polished and tight. I'll get there.
My only complaint (and it's not really a complaint) was that Sketchbook Pro "crashed" while I was working on it and I lost about 30 minutes of drawing. Not sure what happened. The screen just went black and came back up on the apps screen. When I opened the app back up it had reverted to the last saved version (which wasn't much). It appears the same rules may apply to the iPad as any other computer... SAVE, save often.
I didn't put quite as much detail back in as I had in the original... instead I experimented with different layers and brushes and just had fun with it. (after cursing and moaning for about 10 mins about how much I lost). C'est la vie. Live and learn.
The iPad is an amazing little gadget and after a week of the whole family taking turns (very patiently) playing with it, all I have to say is... Do you have one yet? =)