We booked a 5-day private tour with Qing / Discover Beijing Tours in June 2014, and I wholeheartedly recommend DBT as the only way to visit with children! We had 4 adults (including Grandma) and 5 children (between the ages of 8 and 13).
Besides the fabulous sights and the interesting histories (detailed for the grownups, well-excerpted for the children), things we appreciated:
• absolutely punctual transportation (mini van, with seatbelts and a very safe driver, and a constant stash of cold bottled water)
• minimal queues (we would play tourist and snap photos while she got the tickets)
• flexible itinerary. For example, the children loved the pedicab ride in the hutong, so we went back and did it a second time. Also, she heard at the last minute that one of the attractions had changed their opening hours due to a special event, and she was able to rearrange things so we didn’t have to miss it.
• alert to sources of kid-friendly food and clean bathroom locations
Favorite activities were the trip to the Great Wall at Mutianyu; the market (haggling for souvenirs); and the acrobat show
Rei and Family from USA