I think it's great time to invest in ethereum, for it's now worth $300 which is a very reasonable price. I think in a few months this will bring you up to 2x profit. Bitcoin, on the other hand, is at its peak currently, so perhaps it is better to wait for some time within this month if you plan to hold less than a year. Nevertheless, if you plan to hold for several year I would recommend to buy both eth and btc and perhaps more btc than eth because so far it's always better long-term.