Great source book for wilderness crunchy aspects. This book is filled with crunch- feats, encounter information, cover, etc... The encounter system is the shining point of this work- i constantly use it. it is clear cut with good examples, and gives the GM and players alike good ideas of what is happening in an encounter.
The traps are a bit weak and unimaginative. The feats that are there are very cool for wilderness characters, but there is not enough of them!
As far as hard rules supplements go, this really did the job well. my only complaint is the length, it is too short!! I think that it is worth the money, and cheap to print out.