The Cisco small business wireless APs do not require any access controller
I did mention for 'unified management'. One has to consider for the most appropriate future upgrade path, central management still require the Cisco FindIT Managemen. Even if it only 5 APs, one cannot ignore the pure speed and convenience of central management.
The Cisco WAP581 can support over 200 users per unit
Sure, by Wifi specification.. Nearly any 'enterprise' grade Wifi product will claim that on paper as specification. The Ubiquiti AP-AC Lite on datasheet has a 250+ concurrent user support. What all these vendor means, the AP will
connect to maybe 200+ device at the lowest handshake bandwidth (6.5Mbs / MCS0), when it comes to active transfer stream, it a totally different scope.
Currently the Cisco WAP581 list US$ 245 on Amazon, the UAP AC Lite / Mesh is about US$90-99. Throwing additional US$50, you can get 3 Unifi wireless device, I don't see how one WAP581 can go up against Unifi in both coverage and active usage. Though I didn't read though the Amazon listing, pretty sure no Cisco SmartNet warranty coverage (again additional opex) which mean you don't even get firmware upgrade, while Ubiquiti has active firmware developments (as long as Ubnt exist or declare EOL on product).
Don't get me wrong, Cisco has it place but for a small project like this, this ain't Cisco's scene. Consider the opex/capex, resource on at least one CCNA to do basic troubleshoot and maintenance, and weird snob Cisco issue (like I remember 3 or 4 years ago, Cisco has a weird limitation you can't bind one VLAN on more than one SSID... What up with that?!), the cost of annual license for Smartnet warranty service and per device based FindIT Management software license fee, this is all to much to throw. While Unifi has free central management software, cheap capex to add/replace and much more friendly setup all beat Cisco for this scene in my daily experience IMO.