I have been studying for it this summer using the Kaplan book and CD. I pretty much agree with what others have said. The verbal is a real PITA because no matter how many words you know (I memorized all the "top GRE words" listed in the Kaplan book, in addition to every word I saw on the practice tests that I didn't know) they're always going to have words on there you have never seen before. It's really hard to get an antonym question correct when you have no idea what the word means. I also agree that the reason the math is hard is because of the time restrictions. On most of the practice tests I took, would miss anywhere from 2-6 math questions, and they would always be at the end because I would run out of time and have to guess on them. The concepts they test are easy, the problem is they will have dumb quantative comparisons in there like this:
67^76 76^67
Where you have to figure out how to manipulate the numbers to get them in easily comparable forms. I just made that example up, but you get the idea. Most of the hard questions have an easy, obvious way to solve them, but it will be quite time consuming, and a shorter way that requires more thinking to discover. I usually end up taking the long, easy way which wastes time.
I am applying for grad school in EE this fall and have heard that the importance of the GRE can vary greatly from school to school. I have even heard that some engineering programs disregard the verbal scores, so maybe it won't be so bad.