Another great collection. The difficulty seems similar to the first Fiendish collection and the same format of 180 Fiendish and 20 Super Fiendish. The puzzles get harder as you progress through the book. That may seem odd if you expect all Fiendish to be similar but it's true. Approaching puzzle number 150 I was thinking it had been fairly straightforward so far with no triples. Then on puzzle 150 I noted the first one, an open triple. I noted another triple on puzzle 153.
I have been doing the Fiendish and Super Fiendish puzzles that appear in The Times at the end of each week. The ones in the paper almost always seem a lot easier than the ones that appear later in this book.
If you are thinking "why should I buy this book if I can get my fix with the harder puzzles that appear in the paper (which I can get from the website if I don't want to buy a paper)?" then think again. If you are up for the challenge, some of the Fiendish in this book are harder than the Super Fiendish in the paper. As for the Super Fiendish, they do live up to their name!