"Much nicer" is a bit of a stretch (I use a touchscreen laptop with my DAW). The difference between clicking-and-dragging a knob is not that different from tapping-and-dragging one. Same goes for performance; the iPad is not velocity sensitive, and it does not have aftertouch. At that point, you're probably adding in a MIDI keyboard or other hardware, at which point you may as well just perform with a real DAW and leave the iPad at home.