From what I have seen, coins often plummet after being listed on an exchange, this is a great opportunity for a few reasons:

• If you hold the coin and want to totally cash out, selling immediately will often give you the best short-term price, by a significant margin.
• If you want to hold the coin for the future, you could sell half or more of your holdings and buy back at a much cheaper price a few days later.

I don't think it's wise to simply hold through the mass-selling period, it can be a great opportunity. Or if you think the project has a decent future, you can pick up more coins/invest in the coin when it hits rock-bottom after the first days/weeks.