have both much better because you can get profit from both cryptos that have this potential. bitcoin will increase because this crypto is the most a lot of people are interested in. ethereum as altcoin best of course also has a great potential as well to be more than the current value. thus better have both to invest.
Yes, you should buy eth now, the correct time to buy is now. While people are still waiting for the market price to go up again, you will have the chance to get the eth price in a lower amount, and then it can be a good investment in long term. For sure you will earn more profit.