September Gartner magic quadrant for Information Access Technology placed Microsoft as the leader in the space. 

Microsoft Search technologies include SharePoint Search Express, SharePoint Search and Microsoft FAST Search and Transfer.

Below, you will find a couple of links from which you can access the Gartner MQ for free.

http://www.microsoft.com/presspass/itanalyst/docs/11062007forresterentsearch.pdf

http://mediaproducts.gartner.com/reprints/microsoft/vol6/article4/article4.html