We took DD and DS (4 and 7 at the time), and it was too loud for DD. They have "Meteor Showers" that occur about every 15 minutes or so (similar to the T-Storms at Rainforest Cafe) with lights flashing and dinos roaring, etc... There are several different sections of the restaurant, and each has its own Meteor Shower that occur intermittently, so while yours may have just finished, if you are close enough to a different section, theirs may happen sometime within the 15 minute window before your next one.
Personally I wouldn't recommend it for kids under 6, and even then, I would only recommend it if the kid(s) are into dinos. With that being said, I am fully aware that my kids do not react to things the same way all kids do, so it may be perfectly fine for some.