The problem is everyone will have a different opinion, and some people will recommend a coin if they have some and want to sell it.
In general the coins nearer the top of the market have proven themselves more and are safer long term bets. As you go to lower cap coins the risk increases, but then so does the potential for big % increases. So this is why many people suggest to split your coins betwen some bitcoin some top altcoins and some lower altcoins.