After this thread I'm pretty psyched about getting some Ceriths.
That said, I like my nassarias a lot. When I feed the other inhabitants, they come out of the woodwork and I could hand feed them. They have a good bit of personality and like to 'play' a lot. one of them keeps climbing up a jagged overhang on the reef, then lets go, falling down to the sand then doing it all over again. He does this a few times then goes back to eating.
I imagine he's probably saying "wheeeeee" all the way down.