Best Mesh WiFi System

Not sure about best, but this one solved all my problems with coverage in a house with thick plaster walls and even reaches outside to my deck:

https://amplifi.com/amplifi-hd

I use Google Mesh, no complaints and easy to set up.  

Netgear Orbi Mesh - although just like other routers, instead of a clear "best" there are probably several brands/models that would meet your needs.  As in the past, what works well now may eventually need replaced as technology develops further.

The Orbi system works great for me. Although my main server is hardwired, my garage/outdoor system is connected directly to one of the mesh satellites by a very short CAT8 cable and it works perfectly plus gives me enough range to control the server from my iPad while on the porch or the patio. 

So far 4 different systems.
Best value?
Depends on how good a shopper you are.
Best coverage?
Good luck finding anyone here that has compared.
Best form form factor?
Only you know what you like.
All you know for sure is that everyone is happy.
Go for it.