I can confirm beyond a shade of doubt that Pencil input is not up to the standard of accuracy of Wacom's Intuos Pro or Cintiq line--if you're accustomed to Wacom's standard, I highly recommend purchasing a Pencil from somewhere that has a generous return policy so you can see how it fits within your own workflow. I have a light touch and work heavily with thin, tapered lines and feathered strokes, and there's a real weak point there, which is only exacerbated by the lack of a cursor when hovering. Notes does the best job of "faking" stroke accuracy, but it's not viable for finished work, of course.
I will agree that it is worlds better than any Bluetooth stylus on non-Pro iPad models, and for people who favor different styles of mark making, it may very well serve as a viable Wacom substitute! I wish it worked better for me because I hate Wacom the company with a passion