Supporting all the features you’d expect from a MU* client, like the ability to save, customise and connect to many different worlds, ANSI colours and telnet support, Potato is one of the most actively maintained MUSH Clients available. It also boasts support for many more advanced features, including highlights and triggers, spawns, timers, and full Unicode support. Written in Tcl/Tk, it runs on Windows (XP, Vista, 7 and 8), Linux and MacOS X – and even the Raspberry Pi!
You can download Potato from this site. You can also request new features or file bug reports on the Github Issue Tracker. The helpfiles for Potato can also be viewed there.