If you're going on the 100 Mbps package then buying a different router would be pointless as their router is AC and more than capable than transferring way beyond 100 Mbps over 2.4GHz alone and that's even before the 5GHz is used.
Unless your going in excess of 300mbits and beyond, you would be throwing money down the drain. But if you insist you need a router capable of PPPoE through the WAN port. Reputable brands include ASUS, D-Link, Netgear, Linksys Cisco, TP-Link etc.
You should also be aware if got the package with a telephone included then using your own router would not be possible without losing the ability to make calls. This is because the router includes a telephone socket and uses VoIP, and Vodafone will not give the login details which differs from the PPPoE login, to be able to use a VoIP phone. So a workaround is to bridge two routers if you want the phone, or drop the phone completely.
