[lmns]

802.11n with 5 GHz is okayish, but using 2.4 GHz can be brutal. It's not just the bandwidth, the whole frequency band is just bad. My latency regularly goes through the roof and voice calls are noticeably worse than with 5 GHz wifi.

802.11ac mandates 5 GHz, so it's a reasonable baseline. I don't even care if it's SISO, MIMO or whatever as long as I don't have to fall back to 2.4 GHz.