I don't really have time for all these trials. wrt Flyingtablet, your papers are the sort I was looking at earlier myself and I can read them, but glasses help after a while. Minor zoom & pan help me, likewise for POLK.
I can successfully read the Guardian pdf download version of the UK newspaper:
http://www.guardian.co.uk/g24/0,,1820858,00.html
generally without needing to zoom. But after a while glasses help. A little zoom & pan do make it easier.
If you imagine the page at about 70% of the image that appears on download, that is a good impression. (my screen resoloution is 1280x768). As you can see the writing is small, but okay for me. Your eyes may be younger or older....
WRT the buttons, you just can't stop hitting them if you hold the DR1000 in your hand. What's more, you will keep forgetting that the middle bottom button is ALWAYS the menu button & NOT an ENTER function. ENTER is either of the 2 side middle buttons.
It would be a lot easier if there was a stylus menu for standard functions like back, menu, pan, zoom etc dependant on mode along the bottom. As it is you have to keep returning to the menu and it does drive me mad. I am going to try to print out the key shortcuts and stick them inside the cover as I just cannot yet, remember them all.