Personally, I never used iPad, but a drawing tablet (One by Wacom).
In my understanding, using iPad may seem like a great transition from traditional media to digital due to similar comfort zones : Flat surface, Your attention on the same screen as what you are drawing.
But there is still a difference.... The surface is vastly different - Ipads are smoother, less friction than regular piece of paper. Your lines may appear too flowy for your liking, or uncontrollable. Especially with stylus pen... Better if you draw using your fingers in which you have more control and friction.
Unlike ipads, drawing tablets provide the necessary friction (still not so similar as real paper but you can feel it through the strokes) but it's still an awkward position from looking at your screen and not on your hand when drawing. You just need to practice and get used to it.
