From kernel 4.9 to 4.11, I’ve been using these packages on my 2014 Macbook Pro with no wifi problems:
broadcom-wl from antergos repo
b43-firmware from antergos repo, or b43-firmware-classic from AUR.

WiFi did not work with several of the 4.12 kernels:
linux 4.12.x
linux-ck 4.12.x
linux-zen 4.12.x

I played around a bit, and find out if I switched broadcom-wl to broadcom-wl-dkms, then WiFi is back.

However, none of the broadcom-wl-ck packages worked either.

Does anyone else have a similar issue?