It really depends on how well you can pace yourself and how dedicated the professor in charge of the course is. With no classes, I felt like I wasn't taking "real classes" and put less priority on my online courses than the other ones, which could be problematic if it's a demanding course. Luckily (or unluckily, because it was a pain in the butt at the time), the professor in charge of mine was infamous for half-a$$ing the classes she taught, and this one was no exception. It was a joke, pure and simple. The only time I ran into trouble was on the tests, when I kept getting low B's even though I got the answers directly from the textbook...other people taking the class were having the same problem and we discovered that the professor hadn't been paying attention when she made out the answer key and put the wrong answers down.