Are you asking about "ref struct vs ref class" or "ref struct vs native
class" or "ref struct vs value struct"?

ref struct and ref class are related in the same way as native struct and
native class -- there is no runtime difference.  The only thing affected is
that struct, ref struct, and value struct all start with implicit "public:"
and class, ref class, and value class all start with implicit "private:".
ref class and ref struct are both C++/CLI equivalents to C# struct, all
three generate a garbage collected pass-by-ref CLR type, and all three have
different default member visibility.

C++/CLI -------> C#
====================
ref class -----> class
ref struct ----> class
value class ---> struct
value struct --> struct

The C++/CLI keyword "ref" always indicates a reference type (C# class),
while the "value" keyword always refers to a value type (C# struct).

What confuses you is that in C# class and struct mean completely
different things than in C++. In C++, the only difference between class
and struct is whether members are public or private by default. In C#,
on the other hand, a class is a reference type, and a struct is a value
type, and they have nothing to do with public vs private access.

Tom