Any benefit in using an airport express/extreme with a cable router?

No benefit at all, I have found that when using Apple hardware like iPads and iPhones and using an Airport Express or Extreme there are less disruptions in stability and connectivity.

Otherwise when you are already connected through ethernet putting another device in between will only disrupt and slow down internet.

Only when you need port forwarding setup, for running a website for instance, an Airport is way easier to setup than any other router.

For now, don't do it.

Goodluck

Jeffrey

If you are satisfied with the network situation, including WiFi coverage, you get from the provider's router, there is no use for the Expresses as part of the network infrastructure. If you have areas with weak WiFi reception, they may help - tell us about that if that's the case.

Otherwise, you can still use the Expresses for their other two functions: AirPlay and network print server.

It would depend on how concerned you may be about network security from the Internet and how capable your cable router is. The Apple base stations offer limited control over their WAN-LAN interface. Some other manufacturers' routers offer considerably more. Yours may.

FWIW. In my case, I use a Cisco RV180 wired router between my Internet modem and my Apple base stations. The Cisco handles all routing & firewall functions and the base stations provide my roaming wireless network. The Cisco not only allows for precise control of its WAN-LAN interface, it also provides VLAN, VPN, and additional features that my Apple base stations do not.