Previous editions of the PRINCE2 manual were very poorly designed. This one is much easier to use, though still heavy going and not as clear as it could be.
However, this is an essential reference guide to PRINCE2 as it is the official guide. Pure PRINCE2 can be bureaucratic and costly to implement, with limited benefits. However, used as a template, it has many best practice aspects which can be used to develop in-house project methods.
As far as the exams are concerned, this manual is not a substitute for formal training. However, UK employers are now asking for the qualifications on an almost universal basis, so interest can only increase.