From my experience developing C++ on it, 99+% of everything is portable, but the ~1% that isn't, causes a disproportionate amount of annoyances and extra work.

From my experience developing C++ on it, 99+% of everything is portable, but the ~1% that isn't, causes a disproportionate amount of annoyances and extra work. We still have a program that we have to run in an x86 docker container (with all the problems that brings), just to get it to work on our M1 Macs. The being said, the M1 Pro is a more than good enough piece of hardware that I'm willing to put up with this.