A:
I have tried four pens:
The Acer stylus from the Acer store works great.
The Sony Active Pen works also great, but is a little noisy (tap tap tap on the screen).
The Microsoft Surface Pro 3 stylus works okay, but is not as sensitive as the Acer or Sony pens.
The HTC stylus ($10) works okay as a mouse but does not work well enough to produce neat handwriting.
This computer has an N-Trig digitizer. The Wacom pens will not work on this screen.