I only recently discovered this forum (wish I had earlier) and just took my GMAT today. Before I get into any details, here are my past prep results:

Kaplan CATs 1-8 - (520 - 600)
PP1 - 540
GMATprep1 - 630
PP2 - 640
GMATprep2 - 540 (night before the test)

Since all my 600+ scores all occurred recently, I figured I was in decent shape for the real thing. However, I ended up with a mid-500 score. As disappointed as I was, I instantly knew what went wrong. I simply burned out. Last night during my last CAT, I started questioning math problems that normally were a breeze. I started taking excessive time for each question, staring at the problem and rewriting the stem over and over again. My brain basically quit on me. I have been studying instensely for the last 2 weeks straight (by intense I mean locked in a room for 6-7 hours, staying up until 4-5am) and it all caught up to me last night.

As a result, I started panicing at around 11pm last night (which only made matters worse) so I decided to stay up until about 3am reviewing math concepts. Unfortunately, it was too late - my brain needed a break. So this morning I just hoped for the best and did the test. Here's a breakdown:

1.) AWA - super easy topics - boosted my confidence
2.) Quant - the reason why I didn't get over 600. Performed horribly (just as I excepted. However, oddly enough I started strong...I definitely got the first 10 correct - I caught all the tricks, rechecked my work and was on time. Roughly about halfway in, however, things got worse. I started getting tired, and got 3 probablity questions in a row (what are the odds of that) which I admittingly am not strong on, but was hoping for only 1 at the most. As I started taking extra time on the hard questions, I soon realized that I wasn't going to finish in time. I guessed the last 5 questions 4 of which I know I could have answered easily if I had enough time.
3.) Verbal - standard fare, pretty much what's in all the prep guides.

Anyway, sorry for the long post, but this experience was nonetheless a good one. I've already reschduled my exam for mid-January and am definitely motivated to do much better. My foucs will be on quant and espesically time management. I also intend on getting the OG (never even considered it until I found this site). And most importantly, I'm pacing myself this time around. No last minute craming, and no ridiculous study conditions.