It certainly is harder to do GUI in C++, but with all those libraries out there, it's DO-able. One just needs to know how.
GUI creation C# vs C++ isn't even comparable. I love C++, but anything that will go to a customer for daily use is better built in C#. Because there is no way to tell a customer that his wishes, how crazy they may be, cannot be fulfilled. C# is "can do", C++ is "can do for an enormous amount of money to finance our enormous amount of development time" when it comes to GUI creation. And by GUI creation I don't mean two buttons and a textbox.
I miss const-correctness though.