I've had the eero system running now for a couple of weeks and it is working perfectly. Installed in a 3 story townhouse with an eero node on each floor. Good, full speed internet from all floors (the NBN gateway is on the ground floor). Connected the eero to a Telstra Gen 2 Smart Modem and running the eero in 'double' NAT mode without any problems (just plug the eero into the Telstra modem and this is the default setup). I have turned OFF the Wifi in the Telstra modem (the only required config change). Tested in mobile backup mode by disconnecting the NBN from the Telstra modem and eero still working fine. This is why I didn't put the Telstra modem into bridge mode, so the mobile backup function would still work. So far well pleased with my eero purchase.