greenoak
Here's something from my own experience:
I had OG-8 as one of the sources for preparation. Math was very easy there and can't be used as reference, but verbal was on the same level as in OG-11 and very close to the "real thing".
It's true. Math is becomming more and more difficult, for non-quant backgrounds it will be almoust ridiculous soon. That is the reason older prep books are almost useless for math, but for verbal they are pretty good source. Especialy considering that there is always hard to find good source for verbal practice.
The same situation is with paper tests - while they are excellent source of high-quality verbal questions, quant found overthere is almost comic compared to recent questions from GMATFocus and real exams.