Neither. My understanding is that running Ethereum on the Bitcoin Cash blockchain network is a short term bandaid to handle scaling to give more time to Vitalik and the team to come up with a true solution. If I understand that right (and that's a big if) then seems to me that this would dilute the brand at a very risky time and confuse an already cloudy space. I don't think it would be good for price, and since it is stated as a short term fix I don't think it would be good for the Ethereum network in general. There is also always the danger that this short term fix could become permanent, as they so often do and the long term scaling issue never truly goes away.