benpack03,
Your questions have been answered many times throughout this forum. If you take, say, 30 minutes to browse through test-takers' debriefs, you'll amass a great deal of knowledge about Kaplan and the GMAT overall. Consensus seems to be that GMAT Prep, which you can download from mba.com upon registration, is the CAT that most closely resembles the real GMAT, and it has the same interface. It's put together by the makers of the GMAT. MGMAT CAT's are highly regarded. You're granted access to them if you purchase a book from MGMAT, which you'll quickly learn is highly advisable for some specific topics of the GMAT. You can also download Powerprep, which is the GMAT CAT made by ETS before Pearson Vue bought them out (needs verification). You can download that here:
https://www.gorillatestprep.com/gmat_resources.html. My apologies if posting that link is against the rules here. From what I've gathered, Comb/Perm questions can come in any flavor, but they seem to usually reserve them for the "trickier" questions as they regard them as being more complicated. In essence, if you're testing well, you may see a fair amount of them, but if you're quant score is not as high, you may just see a couple of very basic questions. Hope that helps.
