I'm currently using a tablet/laptop with a Wacom digitizer layer (Thinkpad Helix), and although it is indeed a great addition to capacitive screens, I have to say that the Linux support is not as good as it is for Windows. The corresponding driver was not compatible with Linux initially, if I remember correctly the first compatible driver came out with no pressure sensitivity. Even now, I experience lower accuracy and lower performance compared to Windows. The performance issue is a significant delay between the stylus and the actual drawing on the screen, which often beats the point of the stylus because you cannot use it naturally or draw smooth curves as accurately as you would want.

However, for what it's worth, this laptop never was a good choice for Linux, it seems, even though it's a good machine. I have experienced a lot of hardware issues that I didn't get in Windows. I have chosen to stay on Linux anyway, but I'm pretty much not using the tablet feature at all (almost never use the digitizer, never detach the screen because of bad touch support (no right click with long touch or double touch), suboptimal touchpad/trackpad experience, no good virtual keyboard appearing automatically when touching a text field when in tablet mode, screen rotation is not good, one hardware button is not recognized...). None of these issues exist if I boot in Windows but, well, I still don't want to boot in Windows.

I do not exclude that these Wacom issues are just bad compatibility between the digitizer model on my laptop and my Linux distribution (though I don't know any Linux distribution offering a perfect experience with the Thinkpad Helix). It might not be true for all Wacom digitizers and Linux distributions. But anyway, even on Windows, the Wacom stylus does not offer the level of accuracy I experience on the N900's resistive screen; it's actually quite far from it.