As someone who has always been interested in style (which is not necessarily the same as fashion, although they intersect), I've "done it all." I've had the seasonal analysis (winter!). I've had the draping (rich/bright!). Wear only silver. Wear only jewel tones and stark neutrals. The whole gamut.
Well, this is something different. Carol Tuttle's system is about one's personal energy and personality. While there are color guidelines, there aren't too many hard-and-fast rules. What was interesting to me was that the items that matched my "type" in this system (Type 3, with a secondary Type 1) are things to which I had gravitated in the first place -- chunky, interesting jewelry, textures, etc. Like many Type 3s, I have also always gravitated toward wearing a lot of black (which is one of the few no-nos in the guidelines unless one is a Type 4) ... and so I actually took a hard look at myself in a photo where I was wearing a black top. It really did age me much more than the green top of identical cut. So, there's that.
The one problem (and it's minor) is that this book really only makes sense on some levels if one has already taken Carol Tuttle's Dressing Your Truth course (which I have ... the eBook edition of the book is part of the materials). It's hard to imagine some of the things she's talking about without seeing the videos.
Still, it's definitely superior to the previous "systems" to which I have been exposed. I had stumbled on a lot of my Type 3 recommendations by accident anyway, so it's nice to have some validation.