I would like to draw on my new 10" Point of View Mobii, but Sketchbook Express seems to lag a bit with every stroke - i.e. it's not real time. Is that normal? Would this work better with a specific stylus? I got an Allsop stylus with the purchase but kind of get the feeling it's not optimal (and is even less effective than using my finger). Or are there better, more responsive apps?