Personally me prefers ETH. The ecosystem is bigger. If we sum all the tokens the cap of eth will be higher then BTC
Main purpose of any investment is making out as much profit as possible and we both know that Bitcoin is far ahead of Ethereum or any other alternative in returning huge amount.
Ethereum is a very good crypto coin and definitely there is something in it due to which it has remained at the top of altcoins for a long period now but it is nowhere close to Bitcoin in regards of producing profit. Bitcoin is the best investment tool so far.