As idea it is great, as the tooling available in C++ Builder, Delphi, VB 6, C++/CX (WinRT is basically COM with extras) also great.

Using it from MFC, kind of alright.

Using it from .NET, depends if Framework, .NET Native, or modern, with various levels of usability.

Using it from ATL, WRL, C++/WinRT, is a mess unfortunely.