Introduction

Basically, there are three options for using Quill:

1. An active stylus. This requires special hardware in your tablet, but is by far the best choice for writing. Such a special pen only works with one particular tablet.
2. A capacitive pen. For the tablet, this is indistinguishable from finger touches. But at least you can hold a pen in your hand! There is a wide variety of different manufacturers, and they work with every tablet.
3. Draw with your fingers. Clearly this is not very precise nor the way we naturally write...

Active Stylus

Stylus	Image
Thinkpad Tablet Pen N-trig digitizer For the Thinkpad Tablet
HTC Scribe N-trig digitizer For the HTC Flyer / HTC Evo View 4G / HTC Jetstream
Samsung S-pen Wacom digitizer For the Galaxy Note / Galaxy Note 10.1" not the Galaxy tab (without "Note" in the name)

N-trig http://www.n-trig.com is a company that sells a particular hardware solution that is used in a few Android tablets. The active stylus is actually interchangeable between the different N-trig based tablets.

Likewise, the Samsung S-pen is interchangeable with certain Wacom pens.

Capacitive Pen

If there is no special hardware in your tablet to sense an active pen, you can always use a capacitive pen. They can be recognized by their rounded tip, as in this photo:

They are often sold as if they were made for a particular device (for Ipad, for Asus Transformer, for ...) but they are all interchangeable and not tied to a particular tablet. In my limited experience all capacitive pens work about equally well, so I don't have a particular favorite. If you found one that works particularly well for you then please leave a comment!

Motorola XYboard (Xoom 2) Stylus

I still don't know what this one is. It certainly is not a n-trig stylus. It doesn't seem to be able to distinguish pen input from finger touches. My guess is that it is based on the Atmel maxtouch chipset series, http://www.atmel.com/microsite/maxtouch_eseries/. If you have any information please let me know!

Stylus	Image
Motorola Stylus Unknown technology Motorola XYboard 10.1"