When I used T68 for the very first time I was disappointed, it was slower than I was expecting but after I update to the 14-10-2014 firmware I felt a huge improvement and I was happy with that.
I don't use T68 to read but to run "flight navigation" apps, is true!
But I am having an issue with the screen refresh, it gets some "black" shadows every time the screen is refreshed. I wish this could be fixed, because if it is... It will be another market for T68.
Some links about the flight navigation software being used with e-Ink devices:
http://www.tophatsoaring.org/Kobo.html
http://max.kellermann.name/projects/xcsoar/kobo.html
http://forum.xcsoar.org/viewtopic.php?f=3&t=1728