So while in town today I saw this (I also saw a Eavy metal box for 20 odd quid that constituted a metal pencil case tin 2 paint brushes and a couple of small tubs of medium, Jesus) and decided to have it just because I have stopped getting white dwarf but always enjoyed the master classes.
The book itself costs £18 and is about the thickness of a codex. Every page is colour which you would expect from a book on painting. The book contains 13 master classes, mixed between 40K, Fantasy and Lord of the rings (which I don't think anyone in the world actually plays).
The master classes themselves are just what are shown in white dwarf, lots of details and of course top class painting. There are certainly some techniques such as their one for painting parchment and their technique for painting glassware that I will certainly have a go at but there are others that aren't great.
So all in all would I recommend this book? If you don't get White Dwarf regularly then yes however if you do then there is really little point.
On a side note picked up some liquid green stuff a couple of weeks ago and used it to put together my Contemptor and a squad of mark III armour marines, I am going to go out on a limb and say its the best thing GW have released in the last few years.