Which anti-virus solution is best for APT, email security, and data security?

I am the CEO of a company that provides network security and information security solutions to corporate and enterprise companies.

I am currently researching security solutions. What is the biggest difference between Kaspersky Endpoint Security, Trend Micro Endpoint Encryption, Symantec Endpoint Encryption, and McAfee Complete Endpoint Protection? 

Thanks! I appreciate the help.