What are the main benefits of using Mono over Java (or any other "free" or Linux-friendly language/runtime)?
Mono will always trail behind the latest developments in the .NET framework, why would you want to use Mono over another traditional open-source language/framework (Java)?
EDIT: Like someone mentioned below, I guess the root question is, why would you want to use .NET on the Linux platform?
Anyone who uses Mono faces software patent danger from Microsoft.
That's why not only Mono should be avoided for new applications but also C# in first place.
Migrating to Mono only make sense if you already stuck with Windows and want to escape.
Why free software shouldn't depend on Mono or C#