I would definitely say it is worth the $, especially if you can go for about $17! If you are at all interested in the Titanic, you will enjoy the Exhibit.
I will say that the Plaza it is in, called the Mercado, could use some sprucing up. It seemed like they had grand plans for it, but they never really came through. There are a few small shops to go through and a food court but other than that, nothing I would spend any time on. We only browsed everything since we had about an hour to kill before our tour began (we had just missed the last one).