1 x Eero 6 router in small house (950sq/ft), 1 x Eero (wifi5) in garage connected with backhaul ethernet cable.
Approximately 45 devices total including direct ethernet connected desktops, Apple TV, iPhones and many smart home devices from various manufacturers.
Had run this setup for years with Airport routers with excellent results.
Setup of the eero's was simple, straightforward and worked exactly as expected. Setup Homekit Secure router settings in both (with new firmware) and connected all devices
Pros Easy setup good app great interface
Cons unreliable wifi some devices would connect to wrong band (with Band Steering on) some devices would connect to wrong router
While most devices connected to the correct router, there were numerous devices that would connect to the house router (from the garage) and vice versa. So, rather than connect to a device 2 feet away, they would connect to a router 100 feet away through 3 walls.
While this was an issue, the dealbreaker was for no apparent reason, the wifi would drop out 2-3 times a day. Netflix or Youtube would buffer, the network would go down, and then would come back up. Checking the app would show it offline.
In addition, there is no way to force 5ghz band connection, so my Apple TV 4K (2021), a brand new wifi 6 device would connect over 2.4ghz limiting throughput to 70-80mb/s, even though I have a 1GB/s internet connection, and it was 10 feet from the router.