Best Altcoin for 2018? Without a doubt, marinecoin! for the following reasons:

Low marketcap (less than 1mUSD), so there is potential for growth
Been around for years, unlike some coins that have no real history
Excellent dev team currently pushing the project forward
Anybody who qualifies (up to the first 20,000 people) will get 450k MTC airdropped, so the investment is risk free

How many altcoins currently meet the above criteria?

Sounds like all the other shitload of altcoins made in the 2013 era.