jcadencii is designed to use proprietery signal processing engines.It allows Mac users to run some proprietery Windows programs on Mac OS X with a Mac GUI.
There are some free signal processing engines such as praat and efb-gw. efb-gw is buggy and sounds bad at higher pitches. It is also nice to have a free recording tool for voicebanks. OREMO is free, but it does not run on GNU/Linux.
