I've taken several online Masters degree courses and if you take them from a reputable University (I took them from George Washington University), then you will have a way to interact with your classmates and instructor. In fact the discussions can be quite well thought out as people have time to think about their responses before they post them. The work tended to be more in the line of projects than test based training. I do agree with Onyxpurr, a a good school online courses can be quite challenging and much more work than some of the in person classes I have taken.
One of the best courses I ever took was online, but, as with everything else in the education realm, a lot depends on the instructor. A good instructor gives the students the resources to learn and is available for answering questions and can go beyond the planned lesson if the questions lead that way. A poor instructor cannot. Most corporate training I have received was in the latter category. Fixed curriculum with no additional information available and a teacher who knew nothing beyond the fixed curriculum.
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