[Zetmolm]

As to PDFs, stay away from that format if the book is available in another format.

All books that are on Project Gutenberg are also available (for free) in other formats than PDF, which are much better for an e-reader, e.g. mobi for the Kindle and ePub for all others.

People have different opinions on PDF support largely because people have different types of PDFs they want to read. Reflowable PDFs that contain just text are OK on most readers. The problem is with non-reflowable PDFs and PDFs containing pictures or graphs. Then all 5" and 6" readers fail to some extent.

Unfortunately, most publishers of PDFs that contain just text have no idea what they are doing to us and create them as non-reflowable.

If you want to be able to buy Dutch books (is that your native language?), then all devices on your shortlist are OK except the Kindle. All the others support ePub with Adobe DRM, which is the format in which all Dutch books are sold. If you don't care about buying Dutch books, the Kindle is the best value for money.