It depends on the platform. For example, Rider on Mac will not open vscproj/vcxproj files, because it doesn't support C++ really on non Windows. But I think that is mostly because it would need to use a different C++ compiler and that is non trivial. I would imagine it would also struggle with project types that are not normal (VS extensions, installer projects etc) and C++/CLI as that is not supported outside of Windows too (and I think uses the standard vsc[x]proj file format anyway...)