I visited the Edinburgh Dungeon and it was terrible! Do not be confused by the photo where I actually looked scared!
I do think Edinburgh Dungeon would have been a little better if I was with a group of people, but even that wouldn't save this cheesy attraction. It was expensive too - 15.50 pound, I believe it was the most expensive attraction I did the whole trip.
You go through a series of dark rooms and "learn" in a very cheesy way about some of the history of crime and punishment. But often it was just cheesy over the top scenes. There was a boat ride, but I suspect it didn't go very far and I'm not sure what was supposed to actually happen on it because it didn't seem to actually go anywhere or do anything other then be "spooky."
At the end there was a ride where you go up, see a little video where you're sentences to death and get "hanged." This was the only good part of the whole thing, and my picture came out so good that I had to buy one.
Otherwise I just rolled my eyes the whole time and wondered when it would be over. I almost asked one of the staff members how I could get out because it was so stupid.
After going I did find a coupon for 5 pound off admission, which added to the annoyance. However, I didn't necessarily think the price was high for what was offered. There was a large staff and you interacted with a lot of them, so in terms of labor vs price I didn't think that 15 pounds was that high, if you like this sort of thing.
But if you don't like cheesy, fake, scary stuff, DO NOT go to any Dungeons, not the London, Edinburgh, Hamburg, York or Amsterdam Dungeons. It wasn't scary, it wasn't educational, it was just dumb.