What do you mean best coin? Bitcoin included? Because if so, then of course I prefer bitcoin, for all if offers. If you are just talking about alts, I'm still divided in ether, waves and NEO. I know a lot of people hate ICOs, but now that regulation is being done, I really think that we will see a lot of solid ICOs showing up, and right now that is possible because of these coins (ether, waves, neo), specially Ether of course, because it has more supporters.
So excluding Bitcoin, I would go for one of these, because they've created a great platform that gives us a way to support emerging projects.