Well-considered and balanced, this interacts perfectly with PHB weapons and RAW game systems. This is a great way to satisfy players who have a very specific weapon idea for their character or just give more variety to the weapon attacks in the game. Remember, you can give this stuff to monsters, too!
I think the best feature of this module is how easy it is to add into a game. Simply tell the players that the weapons in this book are legal choices. I also like how the Exotic Weapons add a way to keep the weapons themselves relevant as the class abilities and spells start to outstrip them in terms of raw power. Requiring a feat or special training to use one helps balance the power, and their uniqueness helps keep them flavourful. The properties of each weapon help reflect how the weapon really functions and what you can use it for without getting too bogged down in technicality or making them overpowered.
Throw it in your game, it can only add fun.