このページに、ASP.net MVC3は、オープンソースではないライブラリに依存
していると書かれているけど、Mono版MVC3はMS版と比べて
つかえない機能があるってことですよね？
どういう機能が使えないんでしょうか？

http://www.infoq.com/news/2012/05/Miguel-Moonlight

InfoQ: ASP.NET MVC has been open source for a while now. In the past, how much effort was needed
to make it compatible with Mono?

Miguel: It was very easy to get MVC 1 and MVC 2 running with Mono. With MVC3 things changed,
since MVC3 was open source, but took a few dependencies on libraries that were not open source
at the time, or were transitional libraries. So supporting MVC3 was easy, but deploying it was
. It was a very rare to see an MVC3 site deployed with Mono, it was just too difficult.

With the recent opening up of the Microsoft ASP.NET libraries this has changed, and we managed
to make MVC3 work out of the box with Mono.

Finally, for MVC4, we won’t be able to run this for a while, since MVC4 requires us to upgrade the
core ASP.NET engine to support the new async pipeline and currently nobody is working on it.
It will be a matter of whether people care enough to contribute those changes to Mono and make this run.

こっちの対応表もMVC2までしか書かれてないんだね
http://www.mono-project.com/Compatibility