I don't think either of the two projects is going to knock Bitcoin off the throne.
But if I have to choose between the two, it's definitely ETH.
XRP is a shitcoin
Xrp issue is that it's a centralized coin which unfortunately doesn't fulfill the reason behind crypto industry purpose which is mainly based on decentralization. However, on the short term xrp can still be profitable since it's highly connected to institutions which are still in power and ain't going away anytime soon.