I have a number of issues with this tablet but the screen isn't one of them. The Kepler has a 6" HD E-ink screen with a resolution of 1024x758. It also has a frontlight
and an IR touchscreen. This combination give the Kepler a near-cutting edge screen.
Update: A reader has pointed out that this tablet doesn't actually have a touchscreen (this might explain the unusual model number). Instead I think it has an optical mouse (the black square below the screen.)
Onyx has been working on adapting Android to work with E-ink screens since early 2012, but unfortunately they have been working with the same version of Android for all that time. (In fact, I think this is literally one of the tablets that Onyx teased in October 2012.)
This tablet is running Android 2.3 Gingerbread, a version of Android that was released in late 2010.
Gingerbread lacks many features found on later versions of Android, and due to its age it is not supported by as many apps as it used to be. This could present a problem for owners who want to get the most out of their tablet.
It's not clear yet which apps will be on this tablet when it ships. I do know that it will have Onyx's reading app, which supports a wide variety of ebook and office doc formats (including txt, rtf, Doc, chm html, FB2, Mobi, EPub, PDF, and pdb). TTS and annotation should also work well, given Onyx's past devices.
Perhaps this early hands-on video might offer more clues. I cannot see it at the moment due to a limited internet connection. It's also in Russian, of course.
The Kepler is already listed on one Russian retail site with a price of 6490 rubles, or about $204 USD. It appears to be available now, though of course I cannot confirm that.
As much as I might bash this tablet I will say that I think it's a better option that the alternative. Sony released the Sony Reader T1 in 2011 and the T2 in 2012, and both of those ereaders run Android 2.2. They are also much more locked down devices which require hacking to turn them into Android tablets. They also have limits on what you can install thanks to memory and storage limitations.
The Kepler might only be running a slightly newer version of Android but I have high hopes that it will let you install more apps.