At present the price ratio of bitcoin with ethereum is very close to around 0.02 btc / eth, so I think the right choice now is to buy ethereum rather than bitcoin, and when ethereum rises, it's possible we can see again when ethereum reaches 0.1 btc / eth.
That would only be positive if that time bitcoin will also rise, what if ETH will rise and BTC fall back, it doesn't make sense as we all convert into fiat value.