I wouldn't suggest anyone to sell any Bitcoins right now since the price of Bitcoin is going up. Since I like to watch the Altcoins go up in value when the price of Bitcoin goes up, there is a large chance that people could make more Bitcoins from participating in the price uptrend.
The only thing that I don't like about people panic selling is that they usually complain when the price of Bitcoin gets really expensive and they can't purchase Bitcoin cheaply.
We can't know for sure whether it's going up or down from any given point. That's why many bitcoin holders are selling now because they think it's the highest price possible. I personally disagree with them because I think with widwer adoption bitcoin will rise much more in the future.