For day-to-day management, the streamlined Central Administration console provides new tools for throttling activities, such as bulk jobs or asynchronous tasks, to help prevent the server from slowing. Additionally, I liked health reporting, which pointed out where my server configuration could be improved. This information is available from a much improved Web-based administration interface. On the flip side, the new PowerShell command line interface automates common steps. It ships with hundreds of "commandlets" for doing most anything from creating sites to updating user permissions.
It's mainly good to go
Given that I was running beta code, SharePoint Server 2010 was fairly complete and solid. Be mindful that it's 64-bit, so you need Windows Server 2008 and 64-bit Microsoft SQL Server 2005 or 2008. And you'll have a better experience with Office 2010. Otherwise, exercising the beta should give you a head start on planning your migration.
Heck manages portals for a large pharma company and writes about enterprise applications. He can be reached at firstname.lastname@example.org.