Tim, I thought it was a very thorough and challenging test. It is completely true what they say. It is a mile wide, and an inch deep. To answer your questions:
1. I studied for about 6 months, on and off. I used the Sean Harris book, cccure.org website, official ISC^2 study guide, and Transcender exam prep.
2. I felt pretty comfortable going in with the concepts and my level of experience in the security industry. I did a fair amount of studying as well.
3. I passed on my first try, however, that was a surprise. I didn't think that I passed when I left the exam room. I also had no desire to go back and take it again
Much of what I studied wasn't on the test. I believe that the study materials were designed to get you to about 70%. The rest should come from your experience and common sense. This is what made the test challenging to me.
4. I usually don't fail tests, but I hate taking them. I don't know if I test well. Honestly, that's a difficult assessment for me to make.
One word of caution, schedule your test when you think you are getting ready. The test is administered at few locations and you have to schedule in advance. Once you are ready, you don't want to wait another month to take the exam and risk forgetting something.
From reading your posts on this forum, it seems like the CISSP materials should be fairly natural to you. Good luck and let me know if I can help.