Speaking from experience, it is good. Takes a bit of networking know-how to set it up though, and you still need a router. Their consumer oriented stuff like the AmpliFi is quite excellent too and a bit friendlier.
I use an Edgerouter Lite, a Mikrotik switch and UniFi APs for myself and was so pleased I bought the AmpliFi mesh for my parents.
I have a similar setup, without the switch and the Unifi APs are just excellent. Smooth setup, great range.
So, if you can run a cable, I second Unifi.
Op, if you can not run a cable, maybe look into a mesh network. Repeaters "loose" about half of the bandwidth anyway, a mesh might be good alternative.
If you want to set up an open source enviroment, there is libremesh (http://libremesh.org).
If you just want to buy something, there are products from Netgear (orbi), Linksys (Velo) or Ubiquiti (Amplifi). If you have a Fritz!Box-setup from AVM, you might be able to use their mesh features (site in German, because if you have a FritzBox, you probably speak German ;) https://avm.de/mesh/)
> Op, if you can not run a cable, maybe look into a mesh network. Repeaters "loose" about half of the bandwidth anyway, a mesh might be good alternative.
Mesh network simplifies setting up many repeaters, but it "looses" bandwidth the same way (unless you connect it via cable/other frequency band) as repeaters.
If you don't want to pay $80 for the cloud key and don't want to run the controller on one of your machines, the unifi service can also be set up on a raspberry pi pretty easily.
The Unifi controller is a configuration front end for Unifi devices -- data on the network shouldn't be going through it. It might be a little slower to use, though I've never compared it with the cloud key, but for a home setup, that won't matter too much.