I loved being in Athens. The tour was okay, the guide was knowlegeable and friendly. However, in places like the Acropolis where there are crowds of people and other tour groups, it was difficult to hear the guide. I would suggest the use of those headsets so as to hear the guide at all time.
Also because of the crowds, one could not enjoy places at ones leisure. I actually missed my bus, because it took me so long to get down from the Acropolis (Yes the bus didnot wait for me). Luckily the next stop was the New Acropolis Museum, 300m away so it was easy for me to get to and join the tour again.
The New Acropolis Museum is definately a must see. Our guide was very insightful here and could hear her clearly as there were no crowds to compete with.
Personally, I think I would rather take a Hop-on Hop-off bus and a map instead of doing this tour, I would have liked to see more than what was offered on this tour. If you want to enjoy the sites in your own time without the history behind it, then rather not do this tour.