that they were nice, but they'll never do another. Seems to be a common reply I've heard when I ask people about them.
My mother and sisters went on one last year in Europe, they also won't do another. Sister reported that it's a bunch of old people that don't want to do much more than sit, eat and drink local booze. My HS aged niece went along too, that sister had to go above and beyond to schedule interesting things within traveling distance of the port so they could always make it back. Unlike regular cruises, the ship is not the star of the show. The ports are supposed to be and they can be lacking.
In their case, they opted for the Normandy excursion, and it was a long bus ride from the port to and from the D-Day beaches. They ended up having just a couple of hours there before the long ride back. Sounds like the very worst way to do Normandy if you ask me.