Buying stuff is off-topic here, but I do know @anav how to buy on-line (And CA is not on my shops-list). NL,DE,CN is. UK has been dropped now because of Brexit and the new import duties)
To be a bit more on topic: I’m very pleased with the control I have with RouterOS and DUDE. (90 units 1200km from here, MAC access and Romon to the rescue for integrating new units. A mix of PTMP and hAP/wAP/cAP devices in 21 homes with very thick walls and one combined internet uplink of 3 SXT LTE and satellite, a challenge in the Alpes).
Different users every week, with many different devices, some brand new but also very old ones. Living outdoor if they can. Monitoring this is easy with DUDE (and there is more than the network maps, You see all the registrations and roaming with “DUDE/RouterOS info”.) Surrounded by 200 other brand AP’s, that blast at whatever these high power AP’s allow. (Their signal sometimes is as strong as -55dBm, and they are at 1 km.) 2.4 GHz is overcrowded, just even with beacons and AP’s transmitting at 1Mbps. So tuning is a challenge. And the problems and as such the optimisations are different for every MT AP. Now I do have steady performance on all of them. MCS07 encoding for 2.4GHz and MCS09 for 5 GHz. Getting 50Mbps real usage throughput on every one of them on 5GHz (and that is the current LTE limit).
I do miss the possibilities of other brands (http://forum.mikrotik.com/t/802-11ac-wave2-support/127501/1) , and the 802.11ac wave 1 is not even at full power in the MT. And the tuning is “static”. You do not set algorithm parameters, but fixed values. So the MT is not adaptive to changing conditions. It’s trial and error to find out what any of the many parameters in the wireless setting will do or can do. Some are still a mystery (e.g. will a “Max Station Count” reduction give smaller pre-allocated tables, and as such more memory for the buffers and other things?). At least you are not “blind” in what happens in that wifi environment. And as such most problems that where there with the previous equipment have been pinpointed and solved.