Here are some comparisons from the iLiad for you (I'm starting to get more excited about the Boox):
- View PDFs in portrait or landscape
- View single page, or in continuous mode (Note: I like continuous landscape pode)
- "zoom to fit" button
- Zoom in/out buttons
- Zooming by drawing shapes with stylus
- Remembers your history of zoom levels separate from your navigation history (very useful feature!)
- Drawing:
- 4 line thinknesses
- 4 shades (including black and white)
- erase by drawing over a line (but this leaves some ghosting that needs a refresh to clean up)
Also, some battery tests on the iLiad show very little power drain for the Wacom when you aren't touching the screen.