byobu windows can take advantage of gnome-terminal tabs because they are easy to create with a common keyboard shortcut (Ctrl+Shift+T) or with the mouse (right click options or the global menu) and it is possible to move between them using the mouse.
gnome-terminal tabs can take advantage of byobu-windows because they are attachable/detachable and works in the same ssh connection.
A similar project is going on to integrate iterm2 with tmux on OSX. I believe as linux users, we deserve to be spoiled with the best command line tools available ;)
also see http://code.google.com/p/iterm2/wiki/TmuxIntegration