The difference is that the Ethereum platform is Turing-complete. Various new functionality can be developed with relative ease. This makes the blockchain Ethereum often also called programmable blockchain. While Bitcoin has only one function that aims to facilitate peer-to-peer transactions as a digital currency.
means Ethereum is better than bitcoin?
I think bitcoin is still the best right now, and besides I think it's just a confidence factor. bitcoin has greater confidence than ETH.
and also bitcoin is the first coin.