The very moment to buy?
As per my evaluation, ETH is in a good zone to buy some. We can expect speedy growth soon after the bullish market. I strongly advice you to put your $$ on ETH if you want to. By the way, I am not gonna take the risk.
If you would like to be more speculative, try to invest into NEO, NEO is more than 30 times cheaper than in the year 2017.