You will see lots of love for Ubiquiti here, and for good reason. I run Ubuquiti Unifi at home myself, and recommend it to small businesses if they ask.
Our warehouse operation relies very heavily on available and stable wifi. We have close to three hundred devices that hit the wireless network, split between three SSIDs. Earlier this year we launched a refresh of our antique Motorola/Zebra/Extreme system. My boss set one hard rule: if there is a problem we need to be able to call someone and get immediate support, to have a SME we can hold accountable to the problem and solve it. This ruled out Ubiquiti right up front.
We talked with HP/Aruba, Meraki, and Extreme. Ultimately we went with the Extreme solution. The biggest factor was that our current Extreme solution carried us nearly ten years with zero work. The only time I ever connected to the controller was when we added a new AP, and the last time I did that was over four years ago. To say it differently, the network was hands-free, maintenance-free, and hassle-free for us for almost a decade.
We do have a small remote warehouse where we have two Ubiquiti Unifi APs serving a single SSID and fewer than twenty devices. In the two years since installing we have had to physically touch them to power cycle them at least three times. This is not a solid track record, particularly compared to the preceding paragraph.
A friend of mine does public schools (K-12) and they are on Aruba. If memory serves, there are two AAA high schools in the district, plus the middle and elementary schools that feed into them. Add the administration and support buildings and he has a few dozen discrete locations.
He says they have been solid performers for their application, which speaks well for the scalability of that solution.