I am new to the forum. I want to talk about my improvement on this exam. I am a 3rd year medical student applying for the MD/MBA program at my school. So I have to take the GMAT. On the first try, I got a 590. For that exam I only used TPR's Crack the GMAT book and GMAT prep practice tests. I actually got a 640 on one of them so I know I could have done better. Not to mention my test date was exactly a month after my father passed away. So, the program asked me to retake the exam. As a result, I decided to enroll in a Month-long Kaplan Live Online course. I figure that it was the only way I can organize my time with my busy clinical rotations. I watched every class, did all of the previews and review homework's for each class and took many more practice tests and attacked areas with the QBank. I did certain parts of the Official Guide, mostly the hard questions and the questions from the OG assigned to me for homework in the course. The kaplan course was highly worthwhile.

Previous GMAT: 590
Kaplan CAT 1 Diagnostic: 610
Kaplan CAT 2: 600
Kaplan Cat 3: 590
Kaplan Cat 4: 660
GMAT Prep 1: 640
Kaplan Cat 5: 620
Kaplan Cat 6: 610
GMAT Prep 2: 650
Kaplan Cat 7: 690
GMAT Prep 1 (reset) 670
Kaplan Cat 8: 720 - 2 days before exam

Real thing: 690 [88 percentile] (45q 68 percentile; 40v 89 percentile)

I had a hard time during the quantitative section because 2 of my markers were dry, and I had to keep asking my proctor for another. Annoying waste of time. I probably could have broken 700, but my score is more than adequate to get into my program.

So I just want to let whoever is struggling with this test know that it is possible to have significant improvement in this exam if you put your time and energy into it, even with a busy schedule. I am glad this is over.

My experience with the practice tests: GMAT Prep is obviously the closest to the real thing, but I found the real thing harder. Lots of Venn diagram and simple compound interest questions. Verbal was not that bad. Comparable to GMAT Prep and to a lesser extent Kaplan.
As for the kaplan CAT's, they are great for timing purposes because they give all Medium or Difficult problems on their CATs. I thought it was worth taking as many as possible. The Quantitative is very algebra/number properties heavy though, which is somewhat different from the real thing. The verbal can be either impossibly hard or really easy. Subtly different to the real thing but adequate enough for practice.

Needless to say, I wholeheartedly preferred Kaplan's systematic style of approaching questions to TPR's gimmicky style.