It's great. It's complicated. I have a MacBook Pro Late 2013 – very old. NixOS runs totally great! Even the proprietary hardware just works, with the nixos-hardware channel. Battery life is awesome, 4 hours of office work.

There is a snag however: Drivers for the built-in Broadcom Wi-Fi card are unmaintained and bug-ridden. Replacements do not exist either. The driver doesn't work most of the time nowadays and I have to rely on a USB Wi-Fi adapter that is sooo slow.

Maybe more recent Wi-Fi chipsets in Intel Macs are better off. Or maybe you don't need Wi-Fi!