[CMake] Are the poor reviews of Mastering CMake Justified?

[DJ]

I have only very recently encountered the need to use cmake. It seems 
this need came all at once out of the blue.

It appears to me that there is a general perception that good tutorial 
material is in short supply. I have followed various tutorials that are 
available online and find them less than stellar. I am mostly familiar 
with gnu toolchain stuff. I admit that I am biased here because my own 
work presents zero requirement for cross-platform builds. So far I find 
cmake documentation to be considerably inferior to gnu documentation, 
but that's just me.

This all led me to consider purchasing the book Mastering CMake. 
However, reviews on Amazon are generally very critical of the book. It 
is indeed expensive. Should I bother to shell out for it, or do others 
here share this negative evaluation of it? I don't want to waste my money.

Best,

- Jake -