Guided or self tour of Wall and Palace?

My wife and I are going to Beijing in mid November and will be staying near the Olympic Park . We were wondering whether it would be better for us (both financially and more efficient) to do a guided tour leaving our hotel, or taking public transportation to the Mutianyu section of the Great Wall and the Summer Palace. If a tour is a better, does anybody have any reputable companies or groups they can suggest? Thank you in advance.