Programmers are always looking for tools to make things easier. The Terminal program included with OS X is adequate. This alternative makes things a little less spartan. According to the documentation this is an active project where the author implements features from other shells. One thing I find useful is the use of the scrollwheel as the middle mouse button for copy and pasting selected text. It also uses PC (Linux) keybindings such as <Home> (beginning of the line) and <End> (end of the line). What impressed me the most was the way I was able to make changes to the appearance and save them for next time.
To be fair, I’ve only used it twice. As someone who programs shell scripts, I was satisfied at the difference.
This program can be found at http://iterm.sourceforge.net.