It really impossible to guess which Altcoins is most profitable one for investment. If you will manage to invest in right moment each coin will give you a big profit. In my opinion Ethereum is the best altcoin to invest.
I think personal altcoin most profitable in investing is Ethereum and Bitcoin because these coins have blockchain technology and thus other than that both coins also have a good platform and already many people who invest in this coin because good for the future
you are right, investment in the etherium indeed profitable, in addition to the stability of the price is good, this coin is easy to recovery condition down to back green again. etherium for that is the best choice as an investment.