I have reported several bugs that were never fixed. It would be nice to see a firemware upgrade that took care of that.
Long ago, I was able to get a TOC in an epub to use an embedded font. That changed after a firmware upgrade and has never come back. Bookmarking was changed from quick and useful to slow and painful. Links in epubs still do not work. These things are important to me and the sudden lack of development last fall has left me feeling cheated and wondering why I bought this thing. I expected bug fixes and good tech support from my pre-purchase research and that lasted about 1 month after my purchase.
My current experience is definitely going to have an impact on future device purchases.