You can substitute your own fonts via a simple hack. I don't know if it will work with the K3, but it probably will. The K3 is supposed to have multiple fonts built in.

I doubt any ebook format, all of which are based on XML (HTML) will ever display a line of text with the precision of a master typesetter. But as the firmware gets better the readers do better at this. Currently missing on every reader I've owned is a good hyphenation system.

Each generation of readers gets better, and the K3 looks like it will be great. I've got its big brother the DXG and it is great.