Please be aware that Nessus and McAfee are very different beasts. What are you actually trying to achieve? If it is A/V, Nessus is not used for that directly.
Edward L. Haletky
VMware Communities User Moderator, VMware vExpert 2009-2015
Author of the books 'VMWare ESX and ESXi in the Enterprise: Planning Deployment Virtualization Servers', Copyright 2011 Pearson Education. 'VMware vSphere and Virtual Infrastructure Security: Securing the Virtual Environment', Copyright 2009 Pearson Education.
Mcafee MVM is a Vulnerability Manager and its in the same alley as Tenable. I believe that is a good deal, Tenable is a reputable vulnerability management solution, top notch in the industry. I think this is what is being used now by the DISA (Federal Government) now for vulnerability management.