Very much thanks iacci,
that's the information I was really looking for. You covered everything really important!
One question remains: how about the hardware buttons. Do they perform well? With which apps?
Reflow ... 13,3 - yes, you are completely right

I simply am not able to imagine yet. But cropping is a more important fact and you answered that already.
The problems with android 4.0.4 and
compatibility with some apps (TTRSS ?!) I expected. You should probably contact the developer, perhaps it is really just a simple problem with TTRS missing an android system library .... But there is certainly more to come (android 4.4).
Xodo is a very good reader app with multi document support and cloud functionality (dropbox, google, onedrive). But probably it is too resource hungry. Some report this app not working very well on Onyx devices.
Formating: yes, this is a problem on many devices. Solution: you should consider
rooting the device which will give you (theoretically from android 2.2 up) the possibility to use
"app2sd" to move most of apps partially to a specially formatted sdcard. This works pretty well on e.g. my Pocketbook Surfpad 4L. Android is very conservative concerning holding space for the system (which is OK). You should also install an app like
SDMaid (cheap, very good!) which cleans up the cache and other system space that hinders apps from installing. The combination of both gave me the possibility to use 1,7 GB of 2 GB system space with tons of apps

There should be informations how about do rooting in this thread and here:
https://www.mobileread.com/forums/sho...d.php?t=273940 . You can root a device without having to reformat or reinstall your system! It is simple as installing an app.
Speed: surely I don't expect "smart phone speed" from a Freescale 1 GHz processor

I remember my 9,7 Pocketbook 912 with 500 MHz and 256 MB Ram which worked pretty well 5 years ago (
https://www.youtube.com/watch?v=OksWzxZ1knU ). And turning a 13,3 page takes a little bit longer (considering these are one of the first devices out there).
Ghosting: thanks for this information. As long as there is a possibility to avoid that (full screen refresh), that would be OK for me.
Pen: What you described should not happen at all for a device which such a precise pen. And a device that is mainly drive by a pen. This seems not to be a software problem. You should consider return the device for repair or at least contact the store.
I will still wait a little bit after the first "children's diseases" will be cured and if Onyx will hold its promises to release an update to android 4.4 (there is already a prerelease available for testing).
But mainly I
will carefully watch over the process how they will work and react on hard- and software related problems that users have.
Service for such a professional device which such a high price tag is everything!
The Onyx simply meets a lot of my precautions.
I don't expect pocketbook to release the Pocketbook CAD-Reader this year. I read somewhere, that after a lot of software related problems they are very conservative releasing new devices.
Thanks again and greetings
Axel