I bought it more out of reverence for the lesser known creator of D&D. (Heh, while buying it we asked a teenage gamer if he knew the name Dave Arneson. "Nope". Gary Gygax? "Oh yeah.")
The campaign world itself I'll probably never use (much like Greyhawk, Wheel of Time, well most published game worlds).
It has some interesting additions & changes.
A wizard can go without a spellbook if they have special gem that stores their spells.
Gnomes can do more with clockworks and such.
It has a long history that has been impacted by Arneson's gaming through the years.
It's a very interesting setting, but just doesn't suit my tastes.