Most promising alt-coin for 2018 is EOS, without a doubt! It's a game changer people. It allows parallel processing, 50,000+ transaction per second and a proven self governance model. All this just means that it's "one of a kind" in it's speed, security, and decentralization. Other platforms have parts, but not all of the amazing tech that EOS brings to the table. Owning EOS tokens = owning bandwidth on EOS platform. I just put out an article a few days ago titled:

EOS advantages for token holders