In my experience, the people that have acted as their own generals have usually spent half of their savings just in mistakes. Nevermind the value of their time plus the headaches.
I work with a guy who recently sold his home to a commercial developer. Now he's building an 1800 sq ft one-story retirement type home. He decided to be a cheapskate (considering he's only using 1/8 of his sale proceeds) and be his own general. So far, the project is a disaster IMHO. He's had numerous hold-ups because the good subs are working for other contractors and are too busy. Two brick masons refused to do the work because the soffit had already been hung. An electrician refused to mount the electric prior to bricking. And on and on. Plus, he spends several hours a day driving around chasing stuff while he could be sitting in his office making more money than a contractor would have charged to begin with.
I used to think I would act as my own general if I were to build because of my past experience and the fact I have family that's been building homes for years. They'll do the work for me when the time comes. Just make sure it's a good contractor, because I've seen some that can mess up a job worse they you or I (but maybe not my coworker!)