both are incredible, bitcoin is a kings of the cryptocurrency. so that for me bitcoin is a all time 1st choose but ETH raising way is very bright .in future ETH taken more strong postion in crypto market.
I agree that both crypto-currency are capable on and suitable for investment because both are capable to grow and develop in terms of their price , value and mode of transaction. So it doesn't matter wether you will choose Bitcoin or ethereum the point is how you will going to manage it and if you will going to take time to extend effort for it. Because in order to succeed you need to invest not just money but of course time and effort.