If only it were easier to jump to a bookmark. Kindle 1 had a way of navigating directly to the next/previous bookmark, but since then it's been buried in 'View Notes and Marks'. I think it sort of defeats the purpose of having them in the first place. Bookmark navigation should be fast, not 4 or 5 steps.
I'm not picking on Kindle in particular, nobody else does them any better, but bookmarks should be as easy as finding dogeared pages (or other navigational aids) in a physical book and they are not.
For example a two finger swipe could jump to next/previous bookmark. Or the GoTo dialog could include a list of bookmarks (ideally interleaved with defined navpoints).