Yes, those who are on the top 10# or 5# of the coinmarketcap list are the most safest ones, but there are some who are fake ones, like bitconnect, maybe it's price is increasing so quickly, but once that the price of the company drops then it is going to have zero value, because it is an obviously ponzi scheme, you should try to be careful about this token because it is very risky to invest.
ethereum is one of the best, if you are going to go for long term, buy ethereums.