Had Stallman & friends not driven the open source crowd away...
... they would use C# a bit more, and the said group wouldn't be so small.
C# is my language of choice, but I had to give up on Mono. I found it useless even for quick programs for one time use. Programming with Qt is far easier and hassle free, despite of C++. Because of the usual scruples against C++, Qt was the last thing I've tried after my transition to Linux, but once I've tried it, choosing it was a no brainer.
The way I see it, Microsoft is trying to gain wider acceptance for .net. The only way of getting stuff on different hardware platforms is to open it. Porting closed source on different hardware platforms is next to impossible. It's hard even with sources available. Nobody will tackle it just to wrestle with patents and licenses once it's done.