Bottom line: Although pricing has yet to be announced, based on operational and usability improvements, Microsoft Exchange Server 2010 will be a major step up from Exchange Server 2007. A potential hurdle: Support for Windows Server 2003 is dropped in favor of Windows Server 2008 only.

The last big release of Microsoft Exchange, Exchange Server 2007, marked a major change from the previous edition. Exchange 2007 introduced unified messaging, a completely new management client, and improvements to almost every aspect of the mail server, but at the cost of a whopping learning curve for administrators. Admins will have an easier go of it this time around.

Due the latter half of 2009, Exchange Server 2010 is light on wholesale changes and heavy on refinements. On top of noteworthy enhancements for Outlook users, new features also make the operator's life easier -- without introducing entirely new ways of doing things. So if the standby continuous replication feature in Exchange 2007 SP1 improved your operations, or you've been migrating your contractors' e-mail accounts from in-house Exchange 2007 servers to Exchange Online to reduce costs, you'll find much to like in Exchange 2010 as well.

[ See our guided visual tour through Microsoft Exchange Server 2010 highlights. ]

The improvements in Exchange 2010 fall into three "pillars," as they are described in Microsoft marketing-speak: flexibility and reliability, anywhere access, and protection and compliance. While I've listed all the new features of Exchange 2010 in the table below, there are a few that stand out, at least in my mind.

Top new Exchange 2010 features

My No. 1 pick is a small thing with a high impact on users: OWA (Outlook Web Access) support for Internet Explorer (IE) 7 and 8, Firefox 3, and Safari 3. When I was involved in administering an Exchange server for a client, the most frequent issue to come up had to do with the requirement to use Internet Explorer for OWA. Users typically ran OWA rather than an Outlook client when they were at home or on the road. Users with Macs wanted to go with Safari or Firefox, and only reluctantly accepted the need to run IE in a Windows VM. Users with Linux wanted to Firefox, as did Windows users, because IE didn't have multiple page tabs at the time, only multiple windows.