I had all of the EK stuff incl. the workbooks, and I felt that they were quite good. I would even say excellent.
My one gripe was with the verbal reasoning though. Their approach is definitely the right way of doing it in that they teach you to be a better reader and build up that working memory buffer so that you retain the passage on the first pass. However, speaking as someone with weak reading skill, I felt that I would need way more than 3 months to fundamentally change the way I read to fit with EK methodology. Thus I adopted TPR tactics and it seemed to work for the most part.
Now re: the workbook, I felt that the material was at times much more accessible and readable than the content typically found on Kaplan, TPR, or AMCAS stuff and that was good at first in helping me to practice. Those of you who were able to slog their way to the passage about pimping and prostitution will probably agree when I say that the material is not always formal
However, it is also this same content that threw me off. When I went to take 6R, I got creamed on the VR section where I was getting 10s and 11s on EK. The 6R is when I got my first taste of the 7 or 8 question passages that are sprinkled in the VR section and that is something EK doesnt really represent very well. After reading a long passage about some topic youre totally disinterested in and then doing painful questions that cause you to question whether or not you understood the main idea, it's hard to stay focused and do things the EK way.
This is more a criticism of myself for not having started earlier and doing things correctly with the EK way, but for those of you looking at August who are starting just now, the EK way might require more time.