[sowbug]

Google WiFi (not the Nest ones with the built-in microphones). They're fine for most cases, but every so often I'd discover that one had gotten voted off the island, causing the remaining two in the mesh to deliver a weak signal to some of the house.

Another problem with mesh networks in general is that they're very sensitive to placement, because they need to be able to see each other (in an RF sense, not visually) to form the backhaul. It adds an additional constraint on your physical topology beyond the regular one of wanting to use the laptop on the couch and in the kitchen. So you end up moving the mesh nodes to corners of the room where you didn't really want them to be, aesthetically. At a certain point you ask yourself whether it would have been easier to run the damn cable through the ceiling than to play musical chairs every few weeks.