Why not have both of them instead of choosing only one? Both are good coins and even though the price of btc right now is too high, if you purchased back then when you posted this (7 days ago) you'll have almost $5k in profit for 1BTC. That's a really good profit, wouldn't you think? As for Eth it is also a good coin next to btc so your investment will be safe either you invest in any of them but you'll have greater chance if you try both.