Best Mesh WiFi System

Don't care about best. I've been using Tp-Link Deco M5 1300 for about 5 years. Started with four for ~$200 and added 2 more refurbished for $80 to put one out in the shed. The ones in the basement, upstairs office, main floor back hifi and outdoor shed all have Ethernet connections. The fifth is rock solid wifi to the front doorbell cam and the sixth is a spare.
We have WiFi calling and it is solid everywhere.

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.

I've had the Google wifi since it came out and it works wonderfully though my home and back yard.  This has since been superseded by Nest Wifi which adds better range but no ethernet port on the nodes. 
I have 40+ devices (including music streamers, nest cams, TVs, etc.) connected at any given point in time and it works great.

Ok, thanks for the suggestions.  We went with Orbi because we’ve used it before and have been satisfied.  Appreciate the help.

Another vote for Orbi. 

If you want the best, make sure your Orbi mesh is wifi6 too. That’s the newest and we didn’t have any dropping issue anymore. 

I'm an IT guy, and I would say the best mesh system for home use is the Netgear Orbi. Pricey, but I have not seen anything else that works as well. 

Does the “rather large house” have any sort of CAT prewire?  Any properly implemented system of hard wired access points will always outperform a wireless mesh setup no matter how good it is.  

I use and like the Eero Pro 6 Wifi mesh network system for the following reasons:
1. Stable system with up to 1GBps download speeds. 2. Very stable. 3. You can use multiple mesh routers. You are not limited to a certain number of them. 4. Regular firmware updates. 5. Excellent and available support. 6, easy to configure and setup a system. 7. Offer Secure+ system which furthers secured your network. Comes with subscriptions to multiple free useful software. Regular discount coupon codes available to reduce the annual cost of this service. 8. Ethernet ports in the rear of each Pro unit (2).  9 Some integration with Amazon. But not tight or intrusive. 

I went with the Wirecutter's top pick. Their report educated me, too. https://www.nytimes.com/wirecutter/reviews/best-wi-fi-mesh-networking-kits/

doni has already made a choice, but for others who may be interested...

I've been using Asus routers for many years (over a decade easily), so I am partial to the brand and accustomed to the user interface. About 5 years ago when Mesh came on the radar (for me), Asus did a really cool thing - they pushed a firmware update that added Mesh capability to routers that had the hardware to do it. This firmware update allowed Mesh for our home (for free), which has 4 routers covering a 4,000 sqft home and 1 acre of surrounding land.

A while back, I was having WiFi connection troubles with a NAD unit and other devices on a particular router - after struggling with it for a while (Cat cable tested good), I re-terminated the keystone wallplate punch terminal and WiFi has been rock solid on that router ever since.

BTW, two of the 4 routers were 'factory refurb' purchased at discount - I've had no problems with those. I think many people are confused by these types of devises and return them to let their ISP do it - so bargains are plentiful. For myself, I appreciate having all the control over my cable modem and routers, and Asus really shines when it comes to user-controls. I also appreciate the built-in NAS functionality, TrendMicro security and deep-dive usage reporting & statistics (with graphs and history) of these routers.

I highly recommend Asus, one of the few companies that has consistently exceeded expectations - for me that is rare.

For Posterity: 

I ended up with the Linksys Velop 3 node.  Hard wire node 1 directly to router/modem and place in in line of site of 2nd node that sits at other end of house. Then 3rd node at the rig and in line of site of 2nd.  3rd node is hard wired to streamer.  Put the router/modem on a LPS. On  Occasion the router/modem flakes and requires a bounce but other than that its been purdy solid.