@Freeshadow.
Sorry, I can't help with language support. I can just about read some languages (and I mean just about) and would not know if the glyphs are correct or not. In the settings it supports the following, German, Spanish, Polish, Swedish, English, French, Dutch and Danish. The names are in the native language, eg Espanol and they do have Glyphs that look right, to me.
@Elfwreck
Thanks for causing me to 'waste' a couple of hours.
No seriously, it was something I needed to do at some point.
The file system is the same as you are used to, folders ect. There is also a Library view which lists the whole collection without folders, big is not the word if you have collections like ours, however for small collections it is fine and has the added bonus of having a thumbnail view for prettiness.
There is also a favorites list, whether that helps or not with the tagging I don't know.
Now to file formats. This is the list of formats that appear on the box. Ignore any other claims, this is definitive at the moment.
Epub and PDF with or without Adobe DRM. FB2, TXT, HTML, RTF and Mobi without DRM.
I have tried dozens of each type and a few of non listed types and apart from some issues with RFT and an FB2 that FBreader couldn't open, had no problems whatsoever. All appeared to be formatted OK, no split words ect. I was quite surprised, especially considering where some of these came from.
Now about the RTF files that failed. They tended to be older files, none appeared correctly in OoO or Wordpad but when I re-saved them as new RTF files and Text files, all were ok.
I am sure there will be some files that are not correct but I couldn't find any that didn't have an obvious formatting fault.
Interestingly, of the files it does not claim to support, PDB in the following flavours did work fine, PalmDoc, Ztext and one unknown but I am guessing PalmDoc.
These files are not supported and did not work,prc, Zip, LRF, Lit and surprisingly Doc.
All the files tested were pulled of my back up, one had been altered in anyway. All were as originally downloaded from various sources.
I did learn a few other things such as how to get out of a seemingly fatal lock up
and that what appears to be a broken screen controller is not.
Hope that helps.