The most trusted altcoins are obviously ETH and LTC. Both are here for the long run and have a great reputation within the cryptocurrency community. Competitors have to show that they can gain the same amount of trust both of the above are getting.
for myself, if I have to choose LTC and ETH, I will choose ETH, because it is clear ETH has the largest platform with large volumes as well, and often in making smart contracts in ICO projects. and it will be brighter in the future