I took a certification in Microsoft, and all my coworkers are Microsoft Certified, and let me say that most of the Microsoft certification are about the tools, not the language, that's the big difference with the Sun ones.
In the Microsoft tests you will see questions like: "If you want to debug a remote application what will you do...", you will not see that in a
java examination.
I met a lot of certified people in Microsoft (with all the certifications that they provided about .NET) and once I asked to them: "How can I call a constructor of the same instance from other constructor" (in java you do that using this()" and they look me like:
... nobody knows how to do that, I took a look in internet and finally found ":base(...)"... but they does not know that! (I've several samples about the same) and let me say that the coworkers are the best in their field in here (I know that because they are selected from a huge group, and only the best are in that group)
Microsoft are not interested in C# or J# or VB.NET, they are interested in people who can drive the tools made by them.
IMHO