Since I've been going on about digital book readers I decided to invest in one to see what one would do for me.
I chose the Interead Cool-er as it seemed the most open - ie not tied to any book distributor- yet supported a wide range of common fromats including pdf and text - which are particularly important to me as I have a large number of pdf's that I occasionally need to refer to and currently live inaccessibly on a Window live Skydrive.
Basically we're talking about product manuals, documentation and the like, as well as pdf's of medieval texts and other historical stuff.
So I had a sensible use case for the device.
So I duly plugged it into my mac and charged it up - this revealed that the documentation supplied was minimal to the point of obscure, but it did charge and the mac did see it as a valid volume to copy files to, even if something along the lines of 'while charging you will see a red light and a display saying ''usb connection'' would have helped'.
One slight problem is that files copied from (or actually via) a Mac are created with a data fork and a resource fork, the resource fork files having a filename in the format of ._filename, just the way nfs does it when you write files from a mac to unix filesystem - problem that has bedevilled the support of heterogeneous environments.
Unfortunately the Cool-er isn't quite sophisticated enough not to display files prefixed by ._ (which is strange given it's based on a linux kernel and most unix systems do not display filenames prefixed by . by default) - something that didn't faze me but might confuse less technical users of the device.
Otherwise on initial tests of a book in epub format downloaded from project gutenberg and of a pdf of a research paper it worked well.
Page changes involve a shazam style refresh - they're not fast enough to be instantaneous and the buttons require definite pressure but otherwise the device works well with a legible display.
In use the device is lighter than expected, and definitely more plasticy in feel. While it didn't come with a carry sleeve, you probably want to lay hands on something suitable if you were carrying it about regularly in a backpack or briefcase
However after a few minutes the reading experience starts to feel natural enough.
I'll experiment further and report on my experience in due course.