Altcoins with real use case will never disappoint you on the long run ,altcoins like clear foundation ,Hot (hologen) and skycoin will never disappoint because they have a real use case ,if you choose wisely you Wont have anything to worry about.
There are some altcoins that are BIG if you know how to pick them out ,some are backed by popular bigger companies like Microsoft among others.
Do not choose coins because they are mineable or they have implemented POS ,without real use case they will die overtime and lose value.
Premined coins were created for the purpose of making money so we don't have to trust them too much and even now its nothing more than bump and dump tokens or coins.Now again we are going to see a coin from facebook which is still the useless because it backed up by the stable value so bring nothing to the decentralized community and they are trying to keep us trapped.