As someone who compiles c++20 code using the big three daily, MSVC claims conformance faster but in practice it's full of bugs and takes more time to be usable.

As someone who compiles c++20 code using the big three daily, MSVC claims conformance faster but in practice it's full of bugs and takes more time to be usable. E.g. when they claimed concept support, it was not possible to use requires-expression outside of a concept declaration e.g. no if constexpr (requires { foo; }) was a syntax error ; clang wasn't claiming concepts support but I couldn't find a thing that didn't work at the time. Same for coroutines, constexpr, my codebase at some point was littered with workarounds just for catering to MSVC's idea of conformance. Even today it's the compiler for which I have the most open bugs I think. And, to put the nail on the coffin, clang generates consistently faster code in my experience and its of many others, see e.g. this recent thread on r/cpp : https://www.reddit.com/r/cpp/comments/100vctp/msvc_vs_clang_performance_has_anyone_tested/ https://www.reddit.com/r/cpp/comments/100vctp/msvc_vs_clang_...