in my opinion if I may suggest, ETH has the potential for long-term investment, and also I suggest Ripple (XRP) this coin is trending and the graph is very good of course the potential to invest both long and short term. 
Both are good options in long term investment. I think the investment in this period is very important because it will help us to make the best profit. Looking at the future, ETH and Ripple will help our lives a lot and you just need to invest now when the price is very cheap.