I have to start by saying I am very fond of the PDQ system. Its simplicity and flexibility is something that draws ne back to it tiem and time again.
In many respects Teh Zorcerer of Zo is simultaneously the simplest yet most sophisticated version of the rules, and is very well explained indeed. I would single out the magic rules for particular praise - pretty much anythign can be a magical ability, but every magical effect has both a cost (something that is consumed or damaged to power the magic, such as possessions, relationships, health etc) and a catch (an inherent way of dispelling the enchantment, such as time (it only lasts a day) place (it only affects the village), action (only against Talking Animals) etc).
Wilst not essential to the rules, one of the best parts of hte book is the 150 page campaign write up. It is simply boiling with advice, plot hooks and suggestions, as well as story hooks.
This is a book that really rewards multile readings, and I cant recommend it highly enough
[5 of 5 Stars!]