There are a number of companies that play in the Enterprise Search space. I wrote a blog posting a few months ago on Microsoft Enterprise Search. For those of you who missed it, take a look here.
So why is Microsoft the best option for Enterprise Search? For starters, Microsoft is investing heavily in the space across the board: SharePoint Portal Server 2003, Windows Desktop Search, as well as a number of other products that use the same full-text search engine that SPS and WDS use. SPS 2003 and WDS provide a great comprehensive solution today. SPS gives administrators the right tools to setup search as well as provide portal functionality. WDS comes with management and deployment tools to deploy across an Enterprise. With the right group policies, you can provide WDS and SPS 2003 search integration.
Microsoft's search technologies have a number of advantages over other vendors today. For starters, SPS is proven technology with thousands of customers. It provides security trimming, great relevance, exposes a web service to expose search as a service, an API and provides simple/advanced search features. SPS crawls public folders, websites, SharePoint sites, exchange PFs and Lotus Notes DBs out of the box with a strong extensibility model for other repositories. WDS, for desktop search, has won numerous awards and gained a lot of recognition --- as a component of Windows, it's supported and it's free if you have Windows.
What really excites me, however, is what's coming in the next version of search in Office SharePoint Server 2007. Relevance is greatly improved and tuned for the Enterprise; User Experience is enhanced and can be easily customized; intelligent People search is out of the box; my favorite feature, however, is the ability to search Line of Business applications with the new Business Data Catalog feature. You can search business data in LOB apps and databases. This is a core differentiator, and in my opinion, is what Enterprise Search is all about. It's about finding the right information or person while you work irrespective of where the information is - in email, on a file share, in a workspace, in a database or LOB application.
So if you're looking at Enterprise Search for your organization, I highly recommend checking out SPS 2003 today and Office SharePoint Server 2007 when the public beta is released. It really is going to revolutionize the way content is surfaced to Information Workers... Office SharePoint Server 2007 has the additional benefit of providing strong document management and records management features as well as metadata management taking advantage of the features in Windows SharePoint Services "v3".
A customer recently made a comment to me "making the content in a CRM system is going to expose possibly old data". I smiled when I heard that... b/c if the data is old, then if anything, this will make people more accountable since it will be seen/viewed more. And if the data is really old, what use is the CRM system? The customer thought for exactly 2 seconds and said about their own environment: "ahhhh... we'll know exactly how useful the information is in these LOB systems after all!"