I welcome the introduction of the C# version and I prefer if everything is done in C#. Just for being selfish because I am a C# developer and I understand C# quickly. When I see VB.NET code, I subconsiously translate it into C#.
My reasons why I think going with C# is better:
1- There are a lot more C# opportunities than VB.NET. Do a search on dice.com and you will notice that a lot more employers are looking for C# developers.
2- Granted there are developers who can develop in both languages and so that's not an issue, knowing VB.NET only is a disadvantage.
3- With this trend going on over time, it will probably get harder to find good VB.NET developers.
4- Most of the code examples on the web are written in C#, fewer in both and very few in VB.NET only. I think most open source apps are written in C#.
5- I feel Microsoft prefers C# but it doesn't publicly say that! All their apps are written by C++ developers who naturally move to C# when they code in managed code.
6- While most DNN module developers don't care which language the core DNN is using, personally I had to look at the DNN core code to be able to fix a show stopper for myself and I hated looking at the VB.NET. Some time ago I purchases a VB.NET to C# translator so I can migrate DNN to C# just so I can understand the code without being bothered by the VB syntax. I had to look at the DNN core code to fix
this bug.
7- Someone mentioned to fix all the bugs before doing any C# work. As long as there's ongoing development with DNN, there will ALWAYS be bugs. Otherwise we'll wait forever.