Michael told me there are many good guides in Xi'an... he is very modest. He guided us (my wife and me) superbly last month and we highly recommend his service. He arranged a great driver (including from/to the airport) and exceeded all expectations as a guide for the Terracotta soldiers, bicycling the Wall, walking and eating at the Muslim quarter, climbing the Drum Tower, and viewing the Tang Dynasty show. Michael is from Xi'an and his knowledge of it's history is deep.
He is a former English teacher and his spoken English is better than most Americans (oddly, it is better than his written emails). He was happy to make a very customized tour for us. More than just a guide, Michael provided insight to today's life in China. Like working hard to put his 12-year-old daughter through private school, or growing up under Mao's influence, or being followed by the Chinese gov't when he was guiding an American official on vacation. We also had very good guides in Beijing, Chengdu, Guilin/Yangshuo and Shanghai, and Michael had the most professional experience of all 5. He was very responsive to emails in arranging our Xi'an trip.
If you choose to contact him, feel free to use my name for special attention. (firstname.lastname@example.org)
Feel free to contact me with questions. Enjoy China! We found it an amazing place with wonderful people.