Nice one Txtr. Putting that 3m money to good use.
The 5 inch displays have a higher ppi than the 6 inch so text should be a little crisper and if it can be read in landscape you can keep the words per page count up to keep from increasing the page turns by much.
Nice that someone finally took Holly Gates' Blue Chute design and the Osprey concept from 2003 and really built a reader that is a bluetooth phone accessory
of course the real question will be if they can get some presence in the carriers' store fronts to offer them at that price