Bitcoin price today(7, May, 2018) is $9,304.39 USD, declining about 5.81% compared with the open, while bitcoin market cap and the volume in 24 hours is$158,354,669,946 USD and $6,973,620,000 USD respectively.
(From https://citicoins.com/bitcoin/ )
Meanwhile, ethereum price also declined today. $750.54 USD was showed on the price chart, and its market cap went down to $74,512,513,498 USD, which is not as much as last week.
(From https://citicoins.com/ethereum/ )
From the perspective of currency, bitcoin is the real money system. Its total is constant while the quantity of eth is changing. In the long run, bitcoin will deflate continuously. On the contrast, ether will inflate as the legal tender currently. Therefore, from the perspective of cryptocurrency, bitcoin is value-added, but the value of ethereum is not necessarily.
Technologically, bitcoin is the most influential application of blockchain, which created a new age. However, it just limited in the area of cryptocurrency. Nevertheless, ethereum introduces the system of smart contrast, upgrading the blockchain to 2.0, which shows its growth potential.