Terminal-level auto-completion (I don't use this feature so I can't detail how it has advantages over shell-level autocompletion: especially if you use the fish shell or zsh, then it may not be better).Special provision for integrating with tmux (an alternative to GNU screen, and which most people regard as better & faster than screen).Split panes (the sort of thing you can do in GNU screen or tmux, but at the level of the terminal emulator rather than in a program running on the server).
While the original iTerm had a tabbed interface before Terminal did, iTerm 2 again eclipses Terminal by adding: The best GUI application for SSH (and everything else you can do on the command line) is iTerm 2.
