i looked at multiple sources, and the test has almost nothing to do with the questions.
As far as general knowledge goes, i really liked the Dannemiller review mp3s, especially downloading it and listening to it at home, in the car, at night, during dates (well, maybe not, cause ive been married a thousand - er i mean 13 years). The Benzon book is like a summarized bible, and there is a lot of info in it. i do have the older version, however.
Abdi was okay... there were a lot of questions, but the answers were hit and miss in terms of info. Some chapters were well written (especially the one by the pain fellow, who i met once).
painexam.com is a good site, with lots of good questions. I got Jensen, listened to it a couple of times, then decided the info was too outdated and i got tired of wasting time listening to war stories.
on the other hand, as i said before, much of the questions were not "covered" or part of any of these sources. i would study to further your knowledge and to allay some fears about the exam, but i think a lot of the test is more geared towards not being completely clueless, and to try to think through each question, as opposed to, for example, a history exam.
but if i had to choose again, i would listen to dannemiller OR read Benzon, and do painexam.com, and learn as much as possible on the job.