Which project/token has more potential in the future, æternity or Qtum? Which is one is better, and why?
It is better not to compare this coin with fraudulent project Qtum. You can compare with Lisk and Ether, can with rutstock and cosmos.
But this project isn't really like Cosmos or Rootstock, their goals are not the same. This project is attempting to create a new blockchain that is able to scale more effectively. Rootstock is trying to add functionality to the Bitcoin blockchain and Cosmos is trying to make communication and interchangeability between different blockchains more feasible (Qtum is attempting to do the same). Each of these projects provides a different type of infrastructure, so it is difficult to say which has the greatest potential. If Aeternity was adopted by the masses due to its ability to scale, then it would be. If Cosmos succeeds in making it easy to switch form one blockchain to another, then perhaps it would be.
You mentioned 3 very good projects and 1 that has some questions, but is still a good idea. So lets hope they all become wildly successful!
Just my $.02