IIRC, many moons ago at a TechEd conference, that ultimately MS wants items to move from Exchange (such as shared calendaring and contacts) over to SharePoint, so Exchange becomes a pure MTA and email storage host. All the other nice things that come with Exchange like shared/public folders, shared calendars and contacts will all be moved to Sharepoint. So I guess it's a technology that pure-MS houses will have to learn...
The last company I worked with (before starting Uni) had moved a lot on document infrastructure to SharePoint, and in the beginning it was a nightmare, especially how poor the searching for documents was, and the lack (or just the poor implementation) of security controls. IIRC, they had to add a 3rd party search tool before searches actually started to work better/properly (at least what one would expect from Google's level of capability).
Even integration between AD, clients and Office was a step backward, however about the only good point was that it created a central document and forum repository for a company spread across 6 offices across Australia that was easy enough to search... (in theory).
PS. That was at TechEd 2009...