Hi MichelleS,
With a 590, you are closer to a 650 than you probably realize - but if you have been scoring at that same general level on your other Official GMATs, then it's possible that you developed some 'bad habits' during your prior studies that are keeping you from scoring higher. We'll need to define and fix those issues (and ultimately replace those bad habits with new 'good habits') before you will be able to score higher on the Official GMAT. You would likely find the GRE to be easier than the GMAT - but those same bad habits might be ingrained at this point (so you will almost certainly have to work to correct those issues before you will be able to hit your Score Goal on either Exam).
Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
1) On what dates did you take your 3 GMATs and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
2) How long did you study before each attempt? For this recent attempt, how many hours did you typically study each week?
3) What study materials have you used over the course of ALL of your studies?
4) On what dates (or approximate dates) did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
5) When are you planning to apply to Business School and what Schools are you planning to apply to?
If you took your GMAT at a Test Center, then you might also choose to purchase the Enhanced Score Report. While the ESR doesn’t provide a lot of information, there are usually a few data points that we can use to define what went wrong on Test Day (and what you should work on to score higher). If you purchase the ESR, then I'll be happy to analyze it for you.
GMAT assassins aren't born, they're made,
Rich