home in an attempt to improve my WiFi coverage and performance

They are intended to be used in an Unifi system but can be added on to any home router to improve WiFi coverage and speed

I have one paired with an AP-AC-IW-PRO and got excellent coverage

These are incredibly easy to install - just plug in and have great coverage

Great coverage and remote setup

And the coverage and speed seems not too good for my house.

Better coverage than expected and great speeds

Your coverage will vary depending on the size of your house, wall materials and potential interference, but I encourage you to think carefully and buy a smaller setup initially as you can always add more APs later

Great coverage, great speed and easy to install assuming you've got a little technical expertise

Gets great coverage through walls back into bedroom and office without feeling like I'm bombarding my family with wifi waves while they sleep.

Great coverage.

Super coverage, able to handle multiple VLANs, great speed and performance.

So you may also want to invest in a Unifi Security Gateway as well as those don't seem to crash