DHCP Option 61
Sky Broadband (the second largest ISP in the UK) require DHCP Option 61 to use their services. This means, with FTTP, Eero must be connected to a Sky Hub to function correctly.
Third party routers (such as ASUS) now include DHCP Option 61 via a firmware upgrade. I would like to see Eero include it too so the gateway can be connected straight to the ONT and thus eliminate the need to daisy-chain the gateway to the sky hub / third party router.