if you think about it, if Mono really has a good implementation of ASP.NET, there should be very little effort to "support" it, it should just work, but that has not been the case in reality. each new release would fix some bugs and introduce new ones and there were constant efforts to workaround those bugs to "support" Mono.
after Novell fired the Mono team and they started their own company their focus has since been mostly on mobile platforms and tools, so the prospects of it becoming a reliable asp.net platform seemed even less to me.
maybe with more and more of asp.net becoming open source it will get better at some point but again if it does, then there really should not be anything I need to do to support it, it should just work, but somehow I doubt that will ever be the case, it has not been the case in my experience.
I have just changed this site back to adapt to browser language. I actually had it that way for a long time but at one point some bug in mojoPortal came up that made me switch it temporarily to forced to en-US and I forgot to change it back after the bug was fixed. currency will still be formatted according to en-US but otherwise it should adapt now.