This is a fantastic setting with a lot of good artwork. It has a 12 episodic plot point campaign that's designed to take players up to heroic level. Since play time can vary from table to table it throws in optional savage tales which you an interlace with the episodes to stretch out the campaign. Also I think that the game world is open enough to allow for the adventures to spin off from the main plot from time to time and search local ruins or investigate rumors.
I really think that Caladon Falls is best ran with this sort of "add your own color" in mind.
The enemies can be brutal. Most will have +2 toughness and +2 to shaken checks out of the gate for being "wild tainted". Also if they die in melee range of the PCs they'll need to make vigor checks or gain levels of fatigue, which can really accelerate the death spiral as PCs rack of a -1 fatigue here, -2 wound there and so on. I had 1 PC at -5 between 3 wounds and 2 fatigue in the first encounter.
There are no real iconic enemies or personalities in this setting. The enemy is basically a faceless hoard with unnameable evils driving the plot forward with spells and power beyond the PCs' ability to stop. I think this, more than anything else, hurts Caladon Falls. There's no one really to hate, no great betrayers, no significant loss to revenge and so on. Which leads me to...
The plot point is one defeat after another after another. This is the design and point of the campaign, a sort of a "we're losing the war, there's no hope" but this could really feel depressing to many player groups. Particularly in that there's very little the PCs can do about it. The plot marches forward much like the overpowering enemy hoard.
Despite the above I really think this book is worth if you want to run a game in Relic. It has edges and great background material for the setting. I really think the plot point campaign is something GMs should modify to fit their groups. Interlace some minor victories, sell the PCs first on "you love this world and want to save it" before starting to tear it all down, and maybe create your own iconic allies and foes for the PCs to rally behind or against.
I also wouldn't hesitate to add in some dungeon adventuring before or in between some of the episodes and hand out some nice magical weapons and armor. The PCs will need it.
Optionally you can ignore the plot point campaign entirely. Many of the savage tales could be used on their own and out of 150 pages only about 40 or so are dedicated to the campaign.