The new release is "feature complete," which means it contains all the features that Microsoft intends the final public release to have. Microsoft wants large enterprises to give it whirl and see how they like it.
I recently summarized some of the new TCP/IP features of Windows Vista. You can read about them in the article, " TCP/IP Changes in Windows Vista and Longhorn ." You can also read about " User Account Control in Windows Vista " and find a whole bunch of other related info here on our Web site.