Obviously bitcoin. There is no doubt that bitcoin will in top. Bitcoin is more popular and powerful crypto currency than ethereum. It has promising and bright future. The price of bitcoin is far better than ethereum. I think bitcoin will in top.
Eth and bitcoin are two most impressive coins right now in international market and they both are progressing with most accelerated speed. But bitcoin is taking lead and Eth is following it among all altcoins. Bitcoin have showed better performance against Eth but they both are potential coins. And like you have said, there are more chances for bitcoin to be on top after few years.