Just in case the OP didn't know. Visual Studio 2013 Community Edition is free and far better IDE for working in C#. You can also develop against Mono runtime using it.
I have used both and Mono Develop always annoyed me as it's editor just does not "flow" right when you are coding. The intellisense and formatting feels a little clunky
MonoDevelop is free, open-source and runs on almost all modern operating systems. The clunkyness is worth it! ;)