We did it a few years ago; from everything Ive read it doesn't change. It was a cute experience. It's not a big fancy factory like we would expect from US standards. It's an old, historic building and can be a bit jarring.

The guide is adorable and fun, and her name is KoKo (or CoCo). You tour, you pour chocolate into molds and such. Then you get to take it. They also have a shop wher eyou can buy chocolate made by experts.
It's worth doing once if you have an adults-only or adults and older-kid group. If you're going to have to keep the kids interested, if they can't listen to the tourguide and follow directions, it won't be fun for you.
It would even be worth it to walk or take a cab over there and do some shopping, then go back to the ship.