MOBI just a bad joke
For an instance I used Calibre to convert an ePub as AZW3 file. It worked like a charm. While MOBI format is just a bad joke when converting a full of table document AZW3 file is interpreting perfect everything. Not to mention that in MOBI all my *.png files have a white background though they are transparent (see MOBI.png). This is not happening in AZW3 (AZW3.png) file which not only reproduce all the *.png file with transparencies but also interprets perfect all the tables. See attachments.
... and I think AZW3 can be read by any Kindle device.