I bought this book at the current DriveThru price of USD7.50 and at that price it was very good value for money. Having now read through it I think USD10-15 would in fact be reasonable.
I bought this book for a specific purpose - I run a fantasy rpg PBP ( http://rpol.net/game.cgi?gi=33805&date=1254758160 ) and as it grows I had a need for a system to help me run the politics and larger combats which take place in the background.
I spent a while reading reviews of many systems and eventually settled on this for several reasons:
a. It contains BOTH resource management and mass combat in one book
b. The resource management scales down to fairly small settlements which is what I need - not huge empires
c. It has a strong medieval feel
d. The rules, although they are d20-based, are clearly-explained and were easy to adapt to the system I am using (Dragon Warriors)
e. Price is reasonable - some of the games I looked at weigh in at USD40 just for one part of the system
f. The rules for mass combat do not require masses of miniatures or cards - and there are even optional simplified rules for determining the result of a combat without playing it out in detailed.
Once I bought the product I was pleased at its depth, presentation and layout. Although some of the rules are fairly detailed, there are always lots of examples which help clarify everything.
Another handy feature is that the authors take pains to point out certain rules and multiplier factors which can be tweaked to give the game a different flavour or pace.
The only reason that I don't give this 5 stars is that I have not yet playtested the combat part of the rules, which are about 2/3 of the book - however I have run some experiments and they seem to fit in nicely.
[4 of 5 Stars!]