I have RB4011 without WiFi. At home I have Mikrotik RB4011 as main router, and Netgear R7800 (OpenWRT) as Access point. My laptop achieves 750mbps speed on 5Ghz internet (I have gigabit internet). Rock stable connection.
Now I moved temporarily to different location, but here I brought Chateau 12 router with me. I am currently using it as access point only. In order to “feel like home” I connected Chateau 12 router with RB4011 router at my home via IPSEC/IKE2 tunnel and mounted EoIP tunnel on top of that. I bridged EoIP on both ends and now I have home internet at different location. When I connect to Chateau 12 access point (wifi), I get IP address from my home, not from Chateau router. I even wrote tutorial how to set it up.
I wanted to avoid explaining this, because you would suspect this configuration rather than Chateau 12 router, but with some additional testing it just boils down to Wireless drivers/software of Mikrotik. I installed beta3 (see upper comments) and so far everything is stable, but it’s been only few hours, so I will be looking how it will perform tomorrow.