Both Ethereum and bitcoin is a great investment but I think for a 100 dollars investment I think it's better to put it in Ethereum because it is still in a low price and could equal to a higher profit than investing in bitcoin since it's already in a high market ceiling when you buy a 100$ of bitcoin it will be 0.0018 Bitcoin but in Ethereum it will be 0.050 in value. But both of the tokens are a great investment and either way whatever you pick you still for sure going to make a profit and both will take a long time before getting a good profit.