Is there any difference in how the C# compiler or .NET run-time handles verbatim string literals versus using escape sequences (i.e. performance) or is it just a matter of design time style? E.G.:
var pathA = "c:\\somewhere";
var pathB = @"c:\somewhere";
I would imagine they are compiled the same and it doesn't matter, but was just curious.
Any difference here is limited strictly to the compiler; the IL and runtime have no concept of verbatim vs escaped - it just has the string.
As for which to choose: whichever is more convenient ;p I almost always use verbatim string literals if there are unusual characters, as that allows for multi-line strings very easily and visually.
As an interesting case:
bool areSame = ReferenceEquals("c:\\somewhere", @"c:\somewhere"); // true
which tells are they are exactly the same string instance (thanks to "interning"). They aren't just equivalent; they are the same string instance to the runtime. It is therefore impossible that they can be (to the runtime) different in any way.