There are lot of different between bitcoin and ethereum. They are totally different crypto currency with different value. The working sector of both coins are different. Ethereum is a currency that accept most of the coin supported.
Bitcoin and Ethereum both are known for long term as these two have the same behavior but difference also lies in many ways. Demand for both the coins are different, Ethereum has lower price than that of Bitcoin.
The highly rated coin is the Bitcoin and ETH holds the second position in terms of long term investments. You will get huge profit from Bitcoin and lesser from Ethereum but the right strategy is to invest in both so that you get maximum profit.