Came for the first time a little less than a year ago and felt like it was the most in-depth and informative tours ever. We liked it so much that we decided to visit again.
Maybe our tour guide wasn't as charismatic and a lot of the areas we visited the first time were off limits due to active events, but the tour quality declined from our first visit. The tour felt rushed and our guide wasn't as knowledgeable.
Still worth a visit, but it definitely was better our first time.