Cintiq has far higher accuracy compared to the Astropad and Cintiq also has 2048+ levels of pressure sensitivity.
Also, input lag with actual tablets/Cintiqs will be far less than the Astropad.
For casual sketching/scribbling, the Astropad may be OK but for professional level work, nothing comes close to Wacom-powered tablets (and, unfortunately, won't anytime soon due to Wacom's patents).
All real graphics tablets, even ones in the <$100 range, have pressure sensitivity unlike the Astropad and the accuracy is far higher with real tablets.
* Astropad does have pressure sensitivity via the supported pens. * Astropad does provide a visible screen like a cintiq at a much lower cost.
How can you clame it "doesn't come close to a desicated graphics tablet" when you obviously haven't tried it in the preferred setup of iPad + pressure sensitive pen? I'm not saying you're wrong, I'm just saying ita speculation at this point.
Alot of pro artists are using Astropad now, in fact we even had a Pixar animator use and loved it!
PS: We are especially excited for the rumored iPad Pro and stylus
It's not going to replace my Intuos tablets, mostly due to power consumption issues, but it is a killer app for one use case: I can now draw on a crowded airplane. I do not mean sketching; I have worked on pages of my comic on the plane with my iPad hooked to my Air. The only real problem I had is that my usual Illustrator palette setup wouldn't fit on the smaller screen.
But I can sit there in a single seat, with my Air on my lap, and my iPad on top of that, and draw.
(Disclaimer: I beta-tested it.)