It's like you want to compare glass vs wood?
In what aspect you want to compare them? Because the only similarity between this two is that they are cryptocurrencies, except that they are two very different thing.
If you refer which will be the no1 coin, if nothing crazy happens, than its still BTC for a few years I think
Ethereum have smart contracts. And I believe Ethereum have more devs, funds and connections. Of course I want bitcoin to be better but it has to do something and not just linger on being the first decentralized crypto.