150 ETH look that much and it's more by first seeing it. But I'll still choose bitcoin, gonna sell 150 ETH for bitcoin.
I think it is better you buy both, because ETH and BITCOIN has the potential price increase is very high at the end of the year 2018.
I want to have both of it but sadly if the conditions are only given for one choice then you have to choose one of it. But yeah having both and the same number of coins will be the best.