Well thought out tour that gives you a good description of the salt mining history and how the process works. If you don't like being underground, don't go. Otherwise, it's well worth it. You ride a train into the mine, slide down 2 slides, take a small, slow boat ride across the water with a light show, and ride an...
Go in the morning because there can be a big queue. It is a worthwhile visiting. The kids will love it. Don't go if you are claustrophobic. I think 5 euros for the photograph in the slopes is a good value for memories! You can take your own pictures in the entrance with the special uniforms on.
Fun way to learn something about how the region became so rich. German guide (but a multilingual audio device is provided free), miners trains, wooden slides, some silly light and sound effects (but the kids seem to like them so...) Photography verboten, alas.