From a quick Internet search you get the following versions in various distros:
Arch: 4.0.13 in Extra
Debian: 18.104.22.168 in stable, 4.0.12 in unstable.
Fedora: 2.8.8 in stable (20)
Gentoo: 3.0.2 in stable, 4.2 in dotnet overlay.
Mageia: 3.0.6 in stable (3), 4.0.12 in Cauldron.
OpenSUSE: 3.0.6 in stable (13.1), 4.2.1 in Factory.
Ubuntu: 22.214.171.124 in stable (13.10), 4.0.12 in alpha (14.04 alpha 1), 4.2.2 in a monodevelop PPA.
So with the exception of Fedora, all major distros allow you to install a fairly recent version of MonoDevelop with very little effort. And you will find instructions how to build it yourself on monodevelop.org.
Saying that C++ is better than C# is like saying that a rotten apple is better than a rotten banana
Are there any Linux developers that actually like using proprietary C#.NET/Mono Microsoft crap on Linux? That would be ironically hilarious -- you would have to be a masochist to enjoy it. Even if you were programming for Windows, C++/Qt is the best way to go as it is cross platform.