OpenBSD's WiFi support is still the deal breaker keeping me from trying it out. Per iwm's documentation [0], 802.11n only partially works (no 40MHz channels, and limited to 1x1), and 802.11ac doesnt work at all. That means a max link rate of 72Mbps, and a real world speed of maybe half that.
[0] https://man.openbsd.org/iwm