I will settle for one that just synchronizes across all devices. like biology i prefer a mixed os lifestyle, even if I have a mac book and iPhone, My tablets are android just to be safe.
At the moment I manually deleted and re-add chrome bookmarks to Safari every once in a while. This keeps all those fairly close in sync. I have to do the same for contacts, too. fortunately I use google calendar, and gmail already so those stay in sync.