That depends, as always, on where you're campaigning, how much you value official stuff versus d20 stuff, and what your budget is like.
It's more of what you'd expect from the Forgotten Realms campaign sourcebook, but not as crunchy. Some of the regions it covers are Silverymoon, the High Forest, Anauroch and the Border Areas, the Nether Mountains, and the Underdark. There are some rules for wilderness adventuring, including natural hazards (avalanches, forest fires, floods, quicksand...) and tables for random weather and random encounters. There's also some background on the Silver Marches.
There are 6 PrCs: the Giant-Killer (who I think was posted on Wizards website a while ago, because it had no home), Hordebreaker (warrior type dedicated to destroying hordes of orcs or other creatures), Knight Errant of Silverymoon, Orc Scout, Peerless Archer, and Wild Scout. The Knight Errant and Wild Scout gain bonuses on their home turf, so adventuring beyond that really cuts down on their usefulness.
There's a new weapon, the Tiger's Claws, that are basically Bladed Gauntlets done better (crits on 18-20 instead). There are rules for studying at the college of magic, that mean benefits for wizards if they've got extra gold (like access to spells, and creating magic items without the required feats). And a few new monsters.
All in all, not a high-use book unless you're gaming in the area. Some good stuff in it, but more fluff than crunch.