I just got done watching it all. It is definitely the better version to see, but keep in mind that thirty minutes interwoven into a movie that was already 3+ hours in length may make it seem not so different.
The most significant changes are: a small introductory narrative by Bilbo concerning the nature of hobbits, a slight 'beefing up' of the council at Rivendell, (but even with this, they utterly butchered the scene from what it was in the book - which is understandable I guess, it's a movie after all), Galdriel's gifts, and overall an extension of Lorien in general, and a bit better character-development with Boromir and Aragorn. Otherwise, most of the additional footage is added in ways that do not advance the story a great deal.
The "making-of" discs that come with it, though, are pretty much well-worth the price of admission. They are packed with information about how the project came together, and it's a fascinating look at all the stuff you see in the movie close-up. Definitely a worthwhile buy.