<< But I think John Petersen's point was that this fact does not make either language technically superiour. >>

John Petersen is wrong.

<< Unless you can think of a specific reason why a language designed for .NET has an advantage over a langauge adapted to .NET. >>

Your statement says it all. A language designed specifically for .NET can exploit the power of the FCL more so than a language adapted to work with the FCL. Unlike other languages, C# has almost no built-in libraries and relies on the FCL, instead.

Here's a quote from a book from O'reilly : "Many features of C# were designed in response to the strengths and weaknesses of other language..."

Everything points to C# being the next logical step if you're gonna upgrade your skill set.