Pro: Friendly driver, friendly guide. Trez basically gives a free talkshow on the way back. The trip is comfortable - a wel-equipped bus, good breakfast & lunch, etc. You also get to see the huge ravens, which is probably the best part of this tour.
Con: For safety reasons I had to keep focusing on my steps during the walk. In the future, I hope they would provide an option to walk among the Joshua trees, away from any edges.