Well, you've seen the ToC on the Wizards' site, and read the previews about augment crystals and the like. But after just a short thumbing through it, I have to say I'm pretty impressed.
I like the way it's organized. Things are pretty easy to find, though in some cases the illustration for a particular item might actually 3 pages or so over. There are psionic and incarnum items as well.
The relics are interesting. They're not the uber items most folks are used to, but they are still rare and powerful. They demand the character who uses them be of strong faith (clerics, for example), or if not a cleric, a feat that allows a character to be of a very pious nature to use the item. To use them, the wielder has to give up a spell slot of one level or another.
The magic item sets are really interesting. If you have the complete set, other powers or uses can be uncovered.
The illustrations, for the most part are stunning. Some we've seen in the original books where the items came from, but many are new. I have to say this may be one of the best illustrated books I've ever laid eyes on.
I've not had time to read the new pricing guidelines, however. There are tables that offer "level appropriate" magic items, as well, to aid in placing treasure. And a great random item generator that calls to mind the "Diablo" system.
There are better qualified reviewers on ENW than I, but hopefully this helps a bit!