I've had the opportunity the past few months to work with components of Microsoft Dynamics, specifically CRM 3.0.  As a .NET developer and what Microsoft terms an "Information Worker," I have to say I'm highly impressed with this product.

CRM integrates seamlessly into your Outlook client.  In addition, it has a browser based client.  The best selling point, in my opinion, is the customization options.  There is a free SDK for CRM available from Microsoft that enables developers to customize the software, build add-ons, and integrate external corporate applications with the CRM data and functionality.

The implementation procedure for CRM is not overly difficult and there are many configuration and licensing options for small, medium, and enterprise level installations.

Microsoft has improved this product by leaps and bounds over version 1.2.  It definitely rivals, if not out performs, its competition.  I've worked in SalesForce.com and ACT intimately.  I helped build a CRM solution for a large National Laboratory and understand the complex data relationships that are required to warehouse, not to mention display. 

Microsoft has not only made it look easy, but has created a whole new platform to spring from for developers.