Hmmm what is best for this two? I think the best thin to do is for long term because you will see your money is growing and wait for the price get up and trade for the right time than short time.
I think you dont gave to sell all your all altcoins it is better to hold it to get waht you want amount to sell it's worth to wait and wait and see what will happen.
For me I think its much better to hold it for a long time than to buy some altcoin because if you wait you can trade it for the price you want if you wait long and watch it grow.