Had an NBN outage today and was looking around for backup options for next time. Stumbled across this deal on the NetGear LM1200. It is CAT4 (Up to 150Mbps DL, 50Mbps UL). It supports automatic fail over if there is no WAN connection and can operate in bridge mode. Typically retails for around $229 at Officeworks, HN, etc.
For homes with a slow Internet option (DSL) or no Fixed-line broadband service, NETGEAR LM1200 4G LTE Modem provides reliable Internet connection via the 4G network.
CAT 4 is pretty slow. Huawei B818 is CAT 19 and got plenty of listing on Facebook Market.