why would you want to change? If they are being used like home computers then I see no need for any corporate type of antivirus. "If it ain't broke, don't fix it" as the saying goes.
I work for a small business company. My boss has different brands of anti-viruses on the computers. Now they are all home versions. Should we be using home or small business anti-virus? The computers are used like a home computer. We do have company files on a network, but those are kept on an external hard drive.