That's a difficult one: Ethereum is pretty low compared to it's all time high paired to Bitcoin but it didn't go up as many expected with the October fork. And Bitcoin on the other hand is on it's all time high right now. Perhaps it's better to wait and see where Bitcoin is going in terms of correction after fork before making that trade.

On the long run? I don't know what the potential will be of Ethereum: it's stuck around it's current price for a long time now. In terms of investment, Ethereum going for 1000 dollar per ETH would mean 3,5x your investment. At this point to get that return with Bitcoin it needs to go to 18K dollars. So in the long run it looks more likely to 3,5X your investment with Ethereum then with Bitcoin to be honest but I dont know because ETH is pretty much doing nothing in price lately.