In short period = BTC, in long run = Ethereum. It depends on your ROI and investment type required.
Both coins are effective to hold in the future, because we're truly believe that bitcoin price and ethereum price are increasing trends as of now. Moreover this both coin is the most popular coin now in the market, I guess a little bit more time and this coins are reach in to the moon.
Looking forward that this bitcoin and ethereum are not failed to their dreams to become the topest coin in crypto currency industry.