Anything that has the potential to make desktop software better on Linux is good with me. In case anyone hasn't noticed it's in an abysmal state. There are many examples of Linux being a decade or more behind comparable commercial solutions on other platforms. If Mono happens to interest some Windows developers or promote interoperability it would improve the situation greatly in my opinion. As far as patent concerns go with Microsoft -- I say force their hand. Let them litigate if they want to. I think the US DOJ and EU would take a special interest in the case. OSS can't cower in the shadows afraid of big bad Microsoft forever.
The one point I'd like to make is that Microsoft has never threatened to sue anyone over Mono. They made an official agreement with Novell to appease Novell's corporate customers but that doesn't mean they'll sue anyone else. In fact, just the opposite. Scott Guthrie (VP of Development at Microsoft) regularly gives time on his popular blog to Mono projects (see one example: http://weblogs.asp.net/scottgu/archive/2009/02/11/moonlight-...)
The whole "Microsoft Patent" issue is based on the Free Software Foundation stating a concern that Microsoft could someday sue. I don't dispute that concern but understand Mono is very much in Microsoft's best interest because it competes with Apache on Linux.
Finally, as the article points out, even if Microsoft asserts it's patents they'll only be taking away certain support functions like ADO.NET. The heart of Mono is the C# compiler which is an ECMA and ISO standard.
