I've tried the latest firmware updates and at least the 12.12.12 patch. The new .pdf reader works quite nice, love the auto crop feature. The highlighting is still hard to control placement of beginning and ending points and it would be productive to be able to adjust the beginning and ending points after they have been set.
The .epub format on the new .pdf reader is not as good as the old .pdf reader. The body font size does not appear to adjust and just stays small. This is especially true with the Wall Street Journal publication. If you could, I would recommend bringing over the .epub functionality from the old .pdf reader into the new .pdf reader.