Online Classes - Good or bad?

As of this semester, I am taking Online P.E. A bit ironic, I know, but it seems to be working out for me. I have to upload heartrate monitor data once a week and work out at least 4 times a week. It works well for me because I can manage my time with it and I can fit it into my schedule. My question for the fluther is directed towards more academic-based online classes. Has anyone taken them, and, if so, how well did it work out for you? Was it difficult without being able to communicate face-to-face with a teacher?