Another currency or another altcoin? If altcoin then Lets wait for etherium to replace the throne of the king if bitcoin will not implement the lightning network and etherium will in the future successfully feature it Im sure eth will be the next one.
In my opinion, it is very difficult for ETH to beat BTC, if there are a lot of other coin apps that are better than ETH and BTC. However, the difference is that people only believe in bitcoin because their prices are not so volatile
It is difficult to overcome Bitcoin by ETH and this is totally irrelevant to say because we have to know about the prices of both coins then we be able to compare and talk about both the coins. The price of Ethereum is 196 US dollar while that of Bitcoin is 6251 US dollar and both are currently running in their low markets so the difference is clear that it will take long for Ethereum to reach at even the lowest value of Bitcoin.