Which browser or bookmark manager supports folders?

I know that Opera will sync your bookmarks with your computer Opera account when you log in to that account on your phone. The Opera is a good app, I don't like some things about it, I use the default mostly, but will sometimes use Dolphin Browser, or Infinite is one to try out.

But as far as your bookmarks, I guess I would suggest to transfer your Firefox bookmarks to Opera on your computer and then use Opera Mobile and they'll sync.