Haven't used it much, but don't see it as being anything great. One major thing is the site info and history. Other than that, a bit advanced user interface. I'd still use google. I mean they are essentially just doing a google search and presenting it in a different way. I don't think this is meant as a competitor. I guess, amazon just wanted to get into the search game and maybe make some money with sponsored links?
This is my view. How dyou find it? Would you use it over google?