I have done this bible study as part of a group and I have also recommended to other individuals and other groups. I have only ever had excellent feedback form the hundreds of people I know who have completed it.
Beth Moore's style is dynamic and energetic. (There is a video accompaniment which most people enjoy, but I actually found watching her high energy and enthusiasm quite grating!)
The study really has been life-changing for me. It strips us down to the bare bones of our spirirtual life and allows us to really scrutinise what is there. She shows us the better way and leads us there; for me it was quite a painful experience but the benefits and transformation have been wonderful.
Everybody I know who has done this study feels the same; they admit it has been life-changing for them.
It is ideal to do as an individual or as a group. If doing this as a group, there are leaders' materials and backups. I got a lot out of it that way but it was in the quiet times where the real changes happened.