Have just spent a day setting up two mesh networks at different clients. One using BT's whole home wifi solution with 3 nodes and one using linksys's Velop system with 3 nodes. Was interesting.
BT: Easy to setup . Simple app on iPhone to configure. Excellent throughput. Range not as great as was hoped. House is largish but wood framed. One node placed in outbuilding where client (who's day job is wearing a rubber robot mask and running around a giant mining ship with a bum, a cat and a hologram for TV) has a home office. Nodes look very scifi and really good build quality.
Linksys: Set up much more fiddly. Had to reset a node several times to get it working. iPhone app not so straightforward but offers a lot more options. Renaming wifi network doesn't require starting again from scratch as does the BT system (silly). House was an 11th century manor house. Immensely thick walls everywhere which represented a problem even for the mesh system, however we got wifi into most places but will need a fourth node to cover one upstairs corner. Throughput not as high as BT but probably due to the walls. Velop nodes look very nice in place.
Not really much to choose from between the two systems. BT a good £100 cheaper for 3 nodes. Overall I think the Velop is better suited to larger houses due to the extra radio channel. Could do with tweaking the set up app. Back next week to install 4th node.
Overall both clients noticed a dramatic improvement in the wifi connectivity in their homes. Google have also just launched a system. Will return and add to this as and when I have experience of setting up systems from other manufacturers.