I've always been good at math, so my perspective may be distorted. But I'll give it a shot nonetheless:

The Princeton Review and

Kaplan stuff is pretty basic. I think OG may delve a little fruther than those two, but hte OG is quite dry in its guidance. I believe

Kaplan's premiere edition has a section on quant which is quite comprehensive. Not sure which other

kaplan version have it.

That said, what you learn in PR and

kaplan can only take you so far. If you want to score 49-51 and hang with the big boys, you have to start speeding up your ability to handle difficult questions. You need to learn shortcuts. You need to have math truths swirling in your head ready for use.

For example: Even or odd? What is an even number times an even number?

If you need to think about this, you're going to have to straghten out your gameplan. You're behind in the game.

Once you have mastered the PR/

Kaplan quant guides, start pinpointing your weaknesses. Then get the MGMAT quant book that corresponds to these weakness. As a general rule, I'd buy the number properties book since it is the most difficult and refers to divisibility, which is the bain of data sufficiency.