Ethereum is good altcoins, because if it is not why there's a lot of people buy and invest to it? Also, if there's a problems in this altcoins I was sure it was minimize and it can handleable.
Probably that's not enough. A lot of people buying usually is not always a indicator of good project or investment.
May be it is more about the technology, the team and trust it will be up and running for a sustained period of time.