Just checked - and the creators of Typhon III, NGS software, does not have an official comparison between itself, ISS and NESSUS.

I did come across some marketing material from them, make sure you brush your teeth and wash your hands after reading this or any sales/marketing material:

NGSSoftware offer highly specialised cutting edge security software.

Many unique features developed by NGSSoftware over the years set our tools apart from the current range of security products available to the market. Through our research team (NISR) NGS continue to be a world leader in security vulnerability research. Details of which can be seen by visiting our web site http://www.ngssoftware.com. NGS tools are product specific, developed to offer a more comprehensive and detailed security assessment of your network. Supported by a globally renowned team of experts in the field of security and vulnerability research, our tools are continually updated with checks for all the latest vulnerabilities, including those discovered by NGS.

Checks for all vulnerabilities discovered by NGS are added to our tools at the time of discovery, offering our clients zero day scanning capabilities. At any one time NGS has numerous issues outstanding, which are waiting on the vendors patching.

NGS received recognition for their ability in the area of vulnerability research having been voted as having the top 2 vulnerability researchers 'BUG FINDERS' in the world see-
http://infosecuritymag.techtarget.co...art514,00.html

TyphonIII awarded 5 stars and Best Buy by SC Magazine
Individual Review:
http://www.scmagazine.com/products/i...79&type=review
Group Conclusions:
http://www.scmagazine.com/products/i...s&GroupId=6773

Typhon III awarded 5 stars by SQL Server Central
http://www.sqlservercentral.com/colu...gssoftware.asp