I have a 4 story house that is approx 2200 sq ft. I live in an urban area with a ton of interference. This has been my experience and what I ended up having to do…
I started off with 3 AP. They were the AP One Mini’s. Had a lot of coverage issues plus devices would not hand off so nicely between APs. Part of that has to do with the devices but part of it (I believe) is also Peplink related. I’ve tweaked some of the CTS settings to make it better but I would not consider it ideal.
Then - I ran into several devices that just didn’t support a mesh network with multiple APs broadcasting an SSID. Most of these devices end up being IOT type of devices. Ring Doorbell, Kuna Lights, Joule from ChefSteps to name a few. I put in a feature request to allow the AP Standard edition to have Profiles like the Pro edition does. This would allow me to setup an SSID assigned to a single AP (as opposed to all) to get around the problem. You cannot do this at present with the “Standard Edition.”
My final solution…
Purchase 2 Enterprise APs. Placed those on the 2nd and 3rd Floor. Those APs are managed by my Balance One. Repurposed 2 of the AP One Minis for my devices that need a single AP/dedicated SSID. Place one on the 1st floor and 1 on the 4th. Each has it’s own SSID. These devices are NOT being managed by the Balance One since doing so would not allow me to dedicate an SSID. So far it works even though it isn’t ideal. The 2 Enterprise APs have much better coverage and I find the amount of handing off between the devices reduced which has really helped.
YMMV - just one person’s view.