if you looking for the long term investment just go to bitcoin.. because bitcoin is very popular currency than to ethereum now... we know that price of bitxoin is so expensive but this is wort it..
If would also prefer BTC for the both short and long term investment wise. ETH also you can invest some of your funds so that you can have a diversified portfolio and can earn a decent income from any rise in any of the coin. Also after the fork being cancelled the btc is going to spur now.