It is interesting that people have not done more with suspension style equipment before TRX. It isn’t like it there was no suspension equipment available before this. I was using gymnastics rings set low over a mat to work strength 40 years ago. TRX has done an awesome job of bring a user friendly system to our industry. I own two myself. I would recommend that if you do not have any idea how to use them, that you do take the intro courses. And if you are using them, but are not completely comfortable and familiar with the physics involved, use them more and with that purpose in mind. If you have doubts on running a class, take the group class training. I have not taken the classes, but would be interested in knowing if they teach spotting techniques and progressions/regressions, etc. Those are the most important parts of using any piece of equipment with clients.