As I don’t have the devices at home I am not able to show some pictures, sorry about that.
But to help you I will give you a rating for the screen quality:
- iRiver Story HD (EB07, 3rd generation) 10/10
- Onyx M91S 9/10
- Pocketbook 903 8/10
- Asus DR-900 6/10
On the M91S I did not made any annotations on a pdf. With just fingersweeping over the sensor its just undoable to input text. To test this I have to wait for the M90. Making bookmarks on the M91S is quick and easy though.