I would add some reasons why you should buy ethereum:
1) It is still dominating on the ICO market. This was the main reason of its former growth and it can cause future pumps.
2) Technical level of this project is high when we begin to compare it with some other platforms.
3) Ethereum is still strong and there are many people who are interested in its growth.
I believe in ETH future too, and I hope its team will help it with the continuing decline in ICOs and they will come up with some idea of how to save the coin.
As I do have many ETH altcoins, I am not going to buy more. I will hold this cryptocurrency until its price can be at least 3-4 times higher. Probably, more then a year will pass before it happens.