At the end of the day, someone will come here to show you how EOS will be big, that it was created buy the creator of Bitshares and Steem etc....another one will come here to say that ADA will be huge because they want to implement a secure PoS algorithm, sidechains etc...
In my humble opinion only you can make this decision by reading whitepapers and documentatios carefully, research the team, the idea, the potential, it will take several hours but it's your best option
Several hours of research is still a very minimal and over optimistic amount of time. In my experience, this is just the bare minimum to start scratching the surface of a project. For a better understanding of the legitimacy, quality and potential of a project I've noticed it takes weeks, since reading is not enough, for a clear view you also need time for thinking and follow the actual progress of the project.