I have been doing these types of puzzles for a couple of years since discovering them in the Telegraph. I have bought almost all of the 9 Telegraph books and 3 of the O'Ekaki series.
Shopping around for more puzzles (I'm an addict), I never clicked on this book because I was a little put off by the cover design and the name "Paint-doku" is a misnomer, as the principles of hanjie/griddlers/o'ekaki/norograms have nothing in common with sudoku. Eventually (running out of other options) I decided to give it a try and it beats all the competition on a number of levels:
-The puzzles vary in size and difficulty but even with the smaller grids there are no complete no-brainers as is sometimes the case.
-The spiral-bound format is genius, no breaking of the spine necessary, facilitates one-handed completion for, say, when you have to eat but can't stop because your obsession won't let you.
-The paper quality is very good, others have praised its rub-out-ability, but if you live dangerously and complete them in ink you will find that it doesn't absorb and ruin the other side with gel pens (which fill squares in half the time - tip) and biros run quite nicely over it.
-The sheer volume, at over 180 puzzles, with no duds, has kept even a hanjunkie like me occupied for a few months.
In short, buy this and order more pens/pencils while you're at it.