By the looks of it, the ab circle pro was probably never designed for a man in the first place. The exercises mentioned in it, the example workouts with pictures and even the advertisements all have women in it meaning that it was first devised to cater to the women folks and later a management decision made it multi-gender. If so then they have definitely made a huge mistake because the reviews for the ab circle pro are taking a hit and as if that were not bad enough the other successful lines of the company are also suffering because of this.
The design, size, shape and mechanism of the ab circle pro is definitely not meant to produce six packs because that requires a lot of weight training and intensive resistance workouts. The ab circle pro cannot provide both as it incorporates cardio with resistance which is what women actually prefer to use when they workout. That is why the ab circle pro gets rave reviews from women users alone.