Hi,
I've done only a small amount of research, but from the sources I've seen the consensus is the GMATPrep CATs give the closest representation of your real score. My prep was the Kaplan book and OG 13. When I took this test I got:
710 overall; Q42(57th) V46(99th) IR8(92nd).
A week earlier I took a Kaplan CAT:
640 overall Q(76%) V(69%).
With an engineering background I got behind quickly on the GMATPrep quant and didn't recover well, I believe I should score better in most other cases. My question is how much of a fluke was my verbal score? In the practice books I was doing much better in verbal as time went on (maybe 80% correct), but this result still seems unlikely. Also the verbal in the OG seemed easier than kaplan, but I did use the OG second. How much weight would you actually put in to these results?