Yes, it's great. I didn't use other prep. materials very much because I am scoring ~35 on practice tests, but I DID skim some other materials and read the sections which seemed interesting/different from EK.
Things I liked about other prep. materials: TPR has a good strategy for the WS section. Kaplan and TPR offer some additional insights about the VR section, but, so far, EKs verbal advice has helped the most.
For the sciences, I think the EK books are the best. The others seem to go into way too much detail that isn't tested on the MCAT.
Good Luck,
Jota