Time will tell. ETH is and will be strong, how much we will see... Investing now is good but there is a lot of other coins where you can earn more but it's risky 
I think the same as you, should invest in ETH to reduce the risk. Other altcoins do not have high stability. As predicted by many ETH will boom in the future, so if buying ETH now and holding them for long, I think we will never lose. That is my personal thought, I would like everyone to comment.