Well, I'm a month into the ACTUAL writing of the C# 2.0 exam and I'm finding it just as fun as I thought it would be. This exam is more advanced than most people are probably going to want it to be, but I just can't imagine WHY someone would want to take a sissy exam. That doesn't help anyone. On the other end of things, anyone who knows Richter's CLR via C# book by heart should do great on this exam.
The only previews I can give at this time are that this exam is really more of a C#/CLR 2.0 exam as I have a sections for reflection and AppDomain management. I also have sections for more controversial things like COM Interop and unsafe code (not too bad-- I'm not about to ask pointer arithmetic questions!). The other thing I can say is that this complements the 70-* certification exams in that this covers the more technical dimension of the CLR, C#, and the framework. It's more like computer science exams than the certification exams. That is, they are more algorithmic than scenario-based.
As I progress, I'm also setting aside questions for a possible CLR 2.0 exam (for my own exam; probably not Brainbench). I figure this exam could cover things like fusion, assembly loading mechanics, CLR internal memory management, identification of core DLLs ( i.e. mscorwks.dll) and other fun topics. I would really like to see "IT" people think MUCH more like CS people; internals and mechanics are VERY good things to know.