I have done less than 10 hours of .NET programming in my life so I have no idea here... but my impression is that MONO substantially less accepted than a standard Java port... not trying to bash, just explaining my view. I'm moving a significant production Java app from a Linux box to Windows in the next 3 months. My expected work is about 2-days, and frankly my management wouldn't expect more, and I'd have a hard time justifying more (it's probably padded already... don't tell). The portability of Java apps is wonderful. I'd guess MONO could do the same thing, Windows to Linux, but just explaining the run-time to my management or Change Management would require testing, which is cost, which is probably waste, but is also necessary... a Oracle JVM on Linux or Windows, doesn't require the same due diligence.