If you have the option, run ethernet cables to each Wifi location. Using wifi to connect to each unit in most cases will at least half your wifi speed, as it uses the other half as a backhaul between devices. Some work around this other ways, but 90%+ this will be the case. Other than that mesh is awesome as you can walk anywhere and it just works, and with good speed.
Good luck with it.
I use unifi too, great stuff. Couldn't get wifi in the backyard up at the pool but after installing unifi get great reception now. The only weak link in the chain is NBN FTTN. Integrates well with Hassio Home Automation too.
I have tried many and varied.
The first was a cheap wifi repeater I got from China and while it worked it was a real pita.
Then we got the telstra mesh system and it worked sporadically. It did the job but dropped out more than it worked.
Finally I got the Orbi mesh system, and after a bit of stuffing around got it working and have not looked back.
I have a shed up the back where I have my 3d printers in with octopi and wanted to see and control them and the orbi has now been running with 2 raspberry pi's connected for 3 months uninterrupted.
Ubiquiti have a mesh system if you want to use that whilst the setup is a little bit more indepth than others like the google mesh network the performance is great.
I've hear good things about the simplicity of the google mesh networks which the point of mesh is to stay away from the requirement of running ethernet cable. Which costs quite a bit getting a sparky in to do it if you can't DIY it.
All of ubiquiti's newish gear actually has Wifi back links shall ethernet access fails on one device which is great. I also believe they've recently released a phone app to simplify setup of it however if you want to modify it in the future you need to run a server software on windows to edit anything (like wifi name / password) or you can buy one of their "Cloud Key's"
Mesh has a place as a solution to extend networks while provide redundancy to locations which cannot be cabled. If you want performance it is not the correct solution. With each hop the latency will increase and bandwidth will be reduced. There are much better options out there, most of those consumer grade Mesh systems are just for people who are having Wi-Fi coverage issues at home and want to extend their Wi-Fi signal.