Ron Friedmann has reported [Strategic Legal Technology :: Demise of Document Management?] that the UK firm Lewis Silkin is replacing their Hummingbird document management system with Sharepoint.
As I pointed out in my posts last week on the four types of document searches, they lose the critical fetch and recall searches to get a more effective research search. The traditional DM is great system for managing documents; it is not a great system for knowledge management.
I prefer the approach that Tom Baldwin at Sheppard Mullin has taken with layering the Sharepoint search engine on top of the DM system. This gives you the best of both worlds with the great management of the DM and the superior search of Sharepoint.