They said it's based on Roslyn, so it should support VB.net. In the current release of Xamarin Studio for Mac, VB is supported in GTK and console applications, while Xamarin targets only support C# and F#
Given that "Even core features such as C# editing, Xamarin.iOS, Xamarin.Android and ASP.NET Core are implemented as extensions", I assume it'd be relatively easy for them to implement, especially since VB and C# effectively compile the same.
Presumably, C#, Android, and iOS are their top priorities to support, things like VB are less so, but could be added later.
