For the most part, I'm a fan of GMAC, the company that produces the GMAT. I've spent a good chunk of the last decade working as an SAT, ACT, GRE, and TOEFL tutor, and I respect that fact that the GMAT is much more complicated, precise, and nuanced than any of the aforementioned exams. And GMAC is also fairly generous about publishing retired test questions; some of us whine about the GMAT OG's lack of hard questions, but the official guides for GRE and TOEFL are far worse, offering only a handful of (ancient, moldy) practice questions. So while I generally think that GMAC does its job really, really well, they seem to have been a little bit sloppy with GMAT Focus lately. In some ways, GMAT Focus is the best of the GMAT practice material. Sure, it's overpriced ($25 for one test, or $65 for three... basically, you'll pay almost $1 per question). And I think it's weird that they sell the tests in groups of three--you can actually take the test four times before questions start to repeat. And you're given only 45 minutes to complete 24 questions--a little bit odd, since you'll ultimately need to get used to doing 37 GMAT questions in 75 minutes. But GMAT Focus still contains an impressive bank of difficult, fresh GMAT questions; I'm convinced that GMAT Focus questions are much closer to the real thing than any other practice resource available. If you're serious about improving your quant score, GMAT Focus is absolutely not optional.
Unfortunately, the GMAT Focus questions are no longer all that unique. Many of them appear in the 12th edition of the official guide, and I have a funny feeling that even more will show up in the next edition of the Quantitative Review guide. So you might be paying $1 for questions that you've already purchased in another book. That's really annoying, especially if you're already paying for a GMAT tutor.
Even more annoying: the GMAT Focus might not be as representative of the real test as I once thought. For a long time, it seemed that the GMAT Focus would give you a pretty good idea of the composition of the quantitative section--specifically, GMAT Focus included a lot more tricky logic, combinatorics, and "creative algebra" questions than the official guides, and GMAT Focus seemed to be an extremely accurate representation of the actual test. Sadly, something might have shifted, at least a little bit. In the past month, several of my students (all with quant raw scores above 40) whined that the real test didn't have any of the tough combination/permutation/probability questions that appear on GMAT Focus. It makes me wonder whether the GMAT Focus is becoming somehow less indicative of the actual test. Again, I find that a little bit irritating--if it's actually true.
Here's the strangest report of all: one of my GMAT students swears that he saw a GMAT Focus question on the real exam last weekend. He claims that the question was absolutely identical, with the same numbers and everything. He didn't share the details of the question (that would be illegal), but I find that pretty alarming if it's true. Is GMAC getting sloppy? Was the "retread" GMAT Focus question tossed back into the real test as some sort of experiment, or as a statistical control for other questions? Or was my student just hallucinating after a long, stressful few hours of test-taking?
Either way, it's interesting. I still think that it's worth spending $90 for all four GMAT Focus tests, but I couldn't really blame a budget-conscious GMAT student who comes to a different conclusion.