I would be careful if you are thinking about "bridging" - I just installed my eero 3 pack this past Sunday. Two of my eeros were hard wired - my "main" eero (via ethernet) and an "office" eero (via powerline/ethernet). They kept cycling between offline and connected - my other one stayed online for some reason. I contacted support (very responsive - thankyou!!!) and they acknowledged some sort of issue with bridging that was affecting some customers. They are working on a patch for this but recommended I stop using bridge mode for now. Unfortunately my setup kinda requires it - I manage my own firewall and several different subnets etc etc. Instead I unplugged the powerline (office) eero and let it mesh wirelessly and things started working!

So far I am mostly happy - I know this is a constantly improving product and am prepared to put up with minor issues here and there. Would really like greater control/more info etc over the setup but assume that's coming. We do get great signal around the house, speed seems decent - can stream without stuttering - we'll see once the relatives come to town for the holidays! I am still eager to put the powerline connection back in place as soon as things get sorted out.  I've read that wired backhaul is potentially faster/more reliable than wireless. It's very cool that eero handles both.

Should be noted that I have installed 2 other 3 pack eero systems - one for a client and one for my uncle. Both had powerline connections for one of the secondary eeros. Both installations are not bridged and have experienced great coverage and speeds and no issues as far as I know.