If you are interested in details, I recommend reading the following article from Forbes which might prove helpful in making your decision:
https://www.forbes.com/sites/bernardmarr/2018/02/05/what-is-the-difference-between-bitcoin-and-ethereum/#5833e61d7c70
For those who don't like reading a lot, here's a quote I find useful:
"... Ultimately, the long-term growth of any cryptocurrency (or indeed business) depends on useful applications being found for its assets.
If Bitcoin goes on to become a widely accepted form of currency, or the Ethereum network becomes an established standard for distributed computing, then the value of these assets is likely to continue to grow.
On the other hand, in technology, there is always something snapping at the heels of the front-runners. Newer and more efficient algorithms could replace either Bitcoin or Ethereum.
Additionally, both face the threat of government regulation. The value of many cryptocurrencies (including Bitcoin and Ethereum) have moved downwards since the start of the year, which has been attributed to threats of their trade being regulated by governments in China and Korea..."
Hopefully, that might help
