what is the one ALTCOIN you believe in that you will never sell? and why
Personally for me this altcoin is NEM or XEM. I bought it at the very beginning and hold it till now however it has already brought me incredible profits. But I do really believe in it and the technology Mijin which is the core of this blockchain. It's super fast, super convenient in use and super user friendly. So I will sell some part of NEM if only it will reach 10$ per coin otherwise it's my long-long term investment.
I don't know about picking those, they have a lot of nonsense going around their coin. I am sorta investing in Ethereum because it's convenient to me.