For me it seemed like it fleshed out a lot of ideas about what makes good UX. I didn't think it was earth shattering but I think back to it often when I interact with the various items in my life. It's nice for someone to explicitly explain something you intuitively grasp but can't clearly explain.
Here's a little trivia: It was originally titled the Psychology of Everyday things. It was so popular with designers, particularly software designers, that they re-titled it.
