I have been to several of their seminars (Project Management for Administrative Assistants, and another communication seminar whose title escapes me) and I found them to be very worthwhile with one caveat:  I had an instructor for the communication seminar who was obsessed with the events of September 11, and unfortunately, our session was in October in New York City, less than one month after the terrorist attacks.  I could understand her concerns, but she seemed more interested in discussing 9/11 than in any actual communications skills.  At the end of the session, I made some notes on this on the feedback form and SHE READ IT OUT LOUD and identified me in the class!  I was horrified, and will not take a class with her again.  I wouldn't let that color my opinion, since it was just this instructor, not the entire AMA.