(The advantage of McAfee is its super monitoring and better virus detection ability (according to a recent foreign/foreign evaluation, second only to Kaspersky, F-Prot and AVK). Also, it does not require registration and cracking. In addition, McAfee and Symantec are the only two companies that have access to Microsoft's source code
Intrusion / Intrusion Prevention System McAfeeNetworkSecurityManager.pdf)