I like the layout of the CGP revision guides, they're colourful and fun. Therefore I think these guides are easy to revise from because they are able to sustain my interest plus it's always a treat to see the joke at the bottom of the page as a reward for all your revision.
However, I found that in this particular book the writing was very big and extremely spaced out. This gave the impression that they were just trying to fill pages. The content in areas is well covered but in other parts is sparse and a bit basic, for example in the reading non-fiction text section the bit about the headline and presentational devices is too brief considering there is a whole question based around this.
Overall, this revision guide is an excellent summary of the knowledge needed for GCSE English - but should not be used as the sole source or any revision.