While Windows 7 is not the most recent version of Microsoft's operating system, in my humble opinion it is one of the most secure and it is well supported by IT administrators. (Windows 8 does not include Windows XP Mode.)
No matter what the reasons are for staying with Windows XP, its users will be significantly less secure beginning April 9/2014. Vulnerabilities will be forever left unpatched, and attackers are expected to take full advantage of them.
Change is hard, both in terms of moving information and in learning a whole new OS. But if security is important to a company and it should be changing to a more recent and more secure OS is the only option.