Microsoft shipped Site Server and Site Server Enterprise last week. Site Server 2.0 lists for $1499; Site Server Enterprise 2.0 is $4,999. These products add features to Internet Information Server 3.0+, including personalization and commerce capabilities. Like IIS 3.0, however, the servers included in Site Server are a loose mess, not an integrated package. Most of the Site Server components also require SQL Server 6.5 with Service Pack 3.
I attempted to install the Commerce Server component of Site Server Enterprise this weekend but was stymied by the poor installation program: It requires the user to manually setup four SQL Server databases during the install. Until Microsoft creates an install program that does this for you, this program will be too difficult for all but the most proficient Database Administrators.
IIS 4.0 includes slimmed-down versions of Site Server 2.0's usage and site management components for free. Additionally, IIS 4.0 features an integrated management console that is vastly superior to the Internet Service Manager program used by IIS 3.0/Site Server. Unless you need Site Server's features now and are absolutely certain that you know your way around IIS and SQL Server, you may want to evaluate these servers before you buy