It must your absolute own decision in the end but to determine the worth of major alt coins, one need to study well the behavior of the crypto to the dynamic market. Some of the top altcoins right now might not survive the market in the future due to the changes in the trends in the market. Determining which crypto aside from bitcoin to be timeless is all speculation. All of them have risks so, do not invest unless you understand and accept those risks. One can also try to check out major alts that have real use case and have great chance to be adopted and used by significant number of people.