My online course was cancelled twice in a row before I actually got to take it, due to insufficient class size, I believe. The course itself was otherwise convenient. All coursework was to be submitted online, save for the 3 or 4 exams which required in-person attendance at school. In fact, the non-exam coursework itself was completely optional. You simply got extra points on your final grade if you completed all the assignments.
Whether the workload is manageable may depend largely on any other obligations the student has at the time; it's simple to manage on its own, but management may become complicated if other courses and work are being taken at the same time.
Interaction with other students is completely optional (excluding test days) and the course professor was incredibly friendly and made an effort to make herself available to students with questions.