Microsoft's search offering is now split into several products, but the most important distinctions are between SharePoint Server Search and FAST Search Server.
Standard SharePoint server search will offer all the great basic features of search such as:
- best bets
- improved relevance that accounts for popularity and click-throughs
- related popular searches
- overall better organization of the UI (nice callout for people too!)
FAST search will include some new bells and whistles such as:
- Item counts on the facets
- Visual previews of content (the most widely used example was browsing through PowerPoint slides)
- User contexts (one of my new favourite features)
- ... and more
User contexts tie personalization into search by changing the results people see based on who they are. This could be useful in organizations where job roles are pretty well-defined and different people depend on different data to get their job done.
I will dig into this a bit more, especially how to set up this feature, what exactly is changed per user, and how (if at all) it could tie into audiences. Overall though, there are some neat enhancements coming out of SharePoint search!