As a professional .net developer (at least this is how I earn my money) I wonder if Mono for the Mac is worth a closer look.
I already tried Mono 3 years ago when I first got my iMac but the installation was impossible to master and after half a day I just gave up.
I also got help from a Unix professional but we both were unable to get Mono running on my Mac.
Like I said that was some years ago. How is the state of Mono for OS X today? Installation still painful? How about compatibility to .NET Framework 2.0?
Today Mono is quite mature in terms of performance and stability. The current version, Mono 2.4, has a full implementation of .NET 2.0 including ASP.NET. This also supports C# 3.0 and almost all APIs of .NET 3.5, and yes, it supports ASP.NET MVC as well.
My experience with my Mac and Mono is very positive, including for development environment. I prefer to use Textmate + Compiler but there is a good IDE out there: MonoDevelop.
Hope this helps!