ETH or ADA are both good altcoins, the difference between ETH and ADA is, there is altcoin that is good in theory but cannot be tested in the market and so far there has not been significant progress, if ETH clearly ranks second of all available altcoins, and the ETH team is very able to advance the ETH, for example like in 2017 ETH is going up rapidly, although now prices are low but I think ETH will be a surprise again like 2017.