Some will tell you if you have the Schweser notes you don't need to buy any of the texts.
I bought the notes months ago and decided it was not worth saving $600 to not have the source material. I read the assigned readings and then read the notes including working all the problems. Areas of difficulty have me referring back to the texts and even doing some of the problems at the end of the chapter to strengthen weak areas.
I'm just finishing the Quant and this seems to be working well. To put my knowlegde into perspective, I have a BS in business (a minor in applied mathematics) and an MBA. All of the quant material has been review for me, as I suspect most of the curriculum will be. Failing is not an option for me, and $600 is cheap insurance in my opinion.
With that said, it is obvious (from what I've studied so far) that the notes may be sufficient to pass - they are well written and cover the material in detail.