We tested the new software on a couple of test machines, and found it to be very reliable during a couple of days of use. It's not recommended that you install this beta in a production environment, however.
Unlike many Windows service packs, this one adds new functionality. There are four main areas where Microsoft has made user interface changes. They are:
1. Automatic Updates
2. Windows Firewall (previously known as Internet Connection Firewall, or ICF).