Well if you just don't like "banshee" i'm with you there... But I use Mono heavily and its a very stable platform for application development. A language with a good IDE and syntax can greatly improve a developers productivity and help them resolve bugs. Also I wont be a big fan of Ubuntu(which it sounds like your using) until they move there software over to a rolling release and let the developers handle bugs fixes when there found, rather then forcing everyone to use outdated bugged software for 6 months. Maybe Ubuntu 14 will be the one
As a end user your opinion matters, but from a technical stand point, i'm telling you there is nothing wrong with Mono itself. If anything "banshee" was written poorly. When Mono 3 comes out, there will be even more reason for developers to use it as it now has MS's open source stack and huge performance increases. Ill be releasing games for Linux with Mono. Until something replaces C# for my needs I have to use it. At the moment nothing compares for my targets.