Buy them. The altcoins are very cheap and it is so tempting. Just make sure that you know what you are doing. Invest what you can afford to lose. Just the same with gambling, because literally we are like gambling here with a different system. There is always a risk involve here. But the same with every investments. NEO is also in the top 20 most valuable coins right now.
Don't buy them. Actually, you can buy if there is an actual sign of trend reversal. This is usually altcoin-wide changes in trend. Ethereum or Litecoin or even Dogecoin might lead the actual trend reversal for all altcoins - from bear to bull markets - happy times again.