i see the future. ether will be 1k$ in 2018. 
If you really believe that then yes you should buy lots of ethereum, but be prepared in case you are wrong. I personally believe eth is currently a better choice over bitcoin though.
Why do you think that investing all the money in ethereum correctly (although this is a big risk, since the price for it can fall), and investing in bitcoin - does not make sense (although it is more stable)
I adhere to the opinion that all money does not need to be invested in one coin.