If I have to look that hard, then its not worth using. There are -zero- reasons to develop an application with Linux as your target audience to use Mono. Zero. I found it hard to justify using .NET on Windows over Win32, even.
Can you provide any real compelling reasons other than 'stability', which is really subject to how well the developer does his memory management? There is always a potential for said developer to do it better than a VM / Interpreter layer because then he can optimize for his specific use case.