Suggestion: It would be really great to have PDFs formatted for smaller paper sizes. With these PDFs, the font is going to get really small when reading on a remarkable or similar tablets and ebook readers. (Though one can always download the EPUBs and format them into PDF with optimized screen sizes using Calibre).
Regarding the PDFs - I will look into that. I think I always assumed if someone was reading on a smaller screen, an epub would suffice, but I shall see what I can do with the PDFs.
I have also kind of "standardized" on PDF for the way I manage my own collection, because you can always make EPUBs into PDFs, but not the other way around.
If it helps to understand why someone would stick to PDFs: I want to both preserve my ebooks over the long term (decades) and annotate them - comments, highlighting, etc. ePub's format is less stable for the long term, but most of all it lacks standardized annotation (afaict, after some detailed research). Also, if I annotate a book on my computer, I want the same copy on my small screen.
I hope that's helpful!