The new design focuses on the essentials of search and offers a much faster, much more intuitive experience for the user. Gone are some of the supplemental services, such as bookmarks and diary, but in their place is are new "search groups" and a renewed focus on finding information fast. Also included is the best implementation of a "infinite scroll" technique for search results that I've seen on the web.
I think the focus on core search is a good one. And A9 still supports OpenSearch, so third parties can continue to launch their own search engine at A9.com. (The OpenSearch pages now redirect to the community site, which is great, too!)
The look and feel is an improvement, and one that I'm happy to see. I'm impressed with the team for pulling this off.