The big advantage i see with C# is that the vast majority of open source projects, sample code and blog snippets are written in C#. Although it’s easy to convert these to VB.NET with tools (or your head) it is still a monotonous task for VB devs (like me).
Even if you write in VB.NET day to day, you will still need to be able to read C#
Technically, they share the same framework with same performance and memory characteristics and same type systems, so I find it hard to hard to split the two.
Most good developers should be able to shift between the two with a few days adjustment time.
My core frustaration lies with the hundreds of time I have written:
String lastName as String
and wondered why it never compiles!