After what has seemed like an eternity I have managed to achieve my CCNP!
It has taken me over 3 years to complete all CCNP exams.
From my experiences I have found the Cisco certification books lacking in many areas with the exception of the ONT Certification guide - my last exam.
I found this book to be right on the money and coupled with the training materials from the instructor lead course helped me acheive a 934 score. I did make the cardinal mistake of pressing "next" on a lab simulation without answering all the questions. This left me a little nervous for the rest of the exam as soon as I realised what I had done!
For me the hardest exam was the BCMSN, which is very strange considering that my everyday working life revolves around switching! I think I found the wireless elements the most difficult in this exam because we do not have any Cisco wireless infrastructure at my place of work, and the study material didnt cover Cisco wireless very well (at the time).
I found both the ISCW and ONT the "easiest" of the four, but still found each exam taxing. The BSCI was equally as hard as the BCMSN (if not harder in terms of technical understanding) but I think I spent far longer studying for this exam due to the sheer depth of content in the course material.
I spent about 2 - 3 months studying for the BSCI (my first exam), followed by the BCMSN which I spent roughly the same amount of time studying for. I spent roughly 2 months for the remaining two. Obivously I had a sizeable gap between each exam hence the 3 year plus completion time. I am sure that many others have completed the CCNP allot faster, but for me, this way was the best for a work / real life balance.
I think my next step will be CCDP, but I will have a break for at least a year before I begin further studies....