For me you should buy altcoins that is low in value right now and that is Bytecoin, Siacoin, Burst and Dogecoin because if they get low it is just a minimum but if they goes high it will be doubled or tripled.
I don't agree to buy those coins, because all of them only have small volume and it's too risk to hold them in long term.
It's not true, Dogecoin has huge volume and the price seems stable for now. Also risk is still exist whether you trade it short or long term . Most of new altcoins will be pumped instantly because people want to buy it before piump from whales and you can sell it afterwards.