Great tour, especially for people only spending a short time in Xi'an. Guide spoke great English, essentially was a private tour (only the 4 of us that booked it). Highly recommend, especially if you want to have all your plans settled before you get to Xi'an.
I also recommend allowing some time to go see the Bell and Drum tower as well as the Muslim Quarter. You can do this in 1/2 day... it's about the only thing this tour is missing.