iTerm2 is a GPL-licensed terminal emulator for macOS. It was derived from and has mostly supplanted the earlier "iTerm" application. Developed by George Nachman
License: Open Source
iTerm2 offers extensive customization and advanced features, making it suitable for power users, while TotalTerminal provides a simpler, more integrated experience with quick access for casual users. The choice largely depends on the user's needs for functionality versus ease of use.