That's strange. I use Firefox bookmarks pretty heavily and haven't had any of these problems. I type any bit of a URL or title for any bookmark I have in any folder, and Firefox finds it instantly every time. I think I have more than 1,000 at work (internal wikis, blahblah). A large part of my never switching to Chrome came from how much better Firefox worked for bookmarks. I use tags and ability to show tagged bookmarks from the URL bar a lot, especially. (i.e., "tag +" will show all of the bookmarks with that tag, but actually, you don't have to type the '+' unless you want to exclude matching the substring for anything but tags, because it searches tags when you start typing it also)