Update: For reference, 2U has pointed out to me that they were recently recognized by Glassdoor as the 17th-best medium-sized company to work for in 2014. With an average score of 4.2 (based on 21 reviews), this puts them on top of the other ed tech companies discussed here. The only other education company on the Glassdoor best places lists is Edmentum which, oddly, only has a 3.1 average rating based on 37 reviews.
Second Update: All the education companies that have scored well on Glassdoor are coming out of the woodwork now. W.W. Norton has pointed out to me that the have a 4.2 average rating, based on 47 reviews. That puts them tied for first among education companies (that I know of) with 2U.
One way to get a sense of how the companies whose products you depend on are doing is to talk to their employees. This is particularly helpful at times like this, when huge changes are underway. So I thought it would be interesting to take a survey of the employee reviews on Glassdoor of some of the major companies in the industry. The results are revealing, if not entirely surprising.