I passed it about 2 years ago, I studied 90% from Shon Harris' book and then used the official one to go over any trickier areas. The official book is very very dry, Show Harris has a better style but it's certainly worth picking up both just to get full coverage.
From memory, the exam was about 3 hours long, all multiple choice and it wasn't as hard as I expected and there was nothing that wasn't covered between the two books.
There are quite a few different areas that are covered, if you haven't already done Security+ then it's worth doing that first as there is some overlap (albeit Sec+ is lower level) and it's a good introduction to the type of stuff you will just need to learn parrot-fashion (port numbers, etc).
I had been working in IT Security for a few years so had covered about 60% of the CISSP syllabus, of the remaining 40%, only about 10% was tricky and if you find Security interesting then you should find it fairly enjoyable to learn about the ins and outs of some areas like encryption.
You do need to go through each area as there are some parts where they give an opinion you need to remember (even if you disagree with it for your day to day job). Broadly speaking though it is 90% just a memory dump exam, not much thinking required, just cramming up on facts, port numbers, types of encryption, common attacks, etc etc.
The CISA I did a few months after was quite a bit harder, mostly because it deals with opinions much more than facts and is aimed at enterprise level whereas I worked almost exclusively in SMB.
Another point, to get certified you will need to find another CISSP who can sign to confirm your experience (or at least that was the case when I checked about a year ago). It's also worth booking your exam ASAP as they only run them every so often and it gives you a date to work towards. I spent about 2 weeks of evenings and weekends studying but I am pretty lucky in that I have a very good short-medium term memory for exams, depending on how good yours is, you might want to give yourself a month or two (or less if you have a photographic memory).
My email address is in Trust so feel free to drop me a line with any questions. I'm living in New Zealand now so there might be a bit of a delay
