I've only ever read one of her books, and, like about anything else, there are some pretty helpful and interesting things, and some things that just don't make complete sense (like the point about the treats). I do like the personality assessment, and 9 times out of 10 it's right on the money (granted, most of the horses I've 'assessed' I also know reasonably well, so I take that for what it's worth...). I also like the groundwork, personally. I don't have all of the bits and pieces to make all of the obstacles, but I do agree with the basic idea that groudwork translates into and can certainly affect under saddle work. I do find that if I hit a wall, or if my horses are just not focusing as well as I know they can, I step off and put them to work on the ground, step back on in a few minutes and get improvement. I've also put a few horses nearly to sleep with TTouch.
Like anything else, research it, try it, use what works. Obviously the method can get results, but not everything (or every aspect onf one thing) works on every horse.
A stubborn horse walks behind you, an impatient one in front of you, but a noble companion walks beside you ~ Unknown