Virtual Classrooms were the first thing we tried and realized it wasn't for us. We dropped it within a few weeks. I can't imagine spending any significant amount of time stuck with such a finicky and un-reliable medium.

"Look at it wrong and it breaks" is very apt in that situation; All the while they are "taking attendance", and none of the lessons were available for later viewing. Our kids learned more from going through stacks of worksheets* with our help, reading, and just spending time with us as we went about whatever errands.

*worksheets were over 95% of the Virtual Classroom work anyways. The rest was art and poorly thought-out "expiriments", with the occassional form-letter/one-paragraph-a-week "essay". Not even book reports or recommended reading!