If you already have it, go ahead and give it a shot. You can also install a product like GEARS from OPSWAT (free for up to 25 pcs). It'll do a daily scan (cloud-based) with other antivirus programs to give you peace of mind that McAfee isn't missing anything big. If you find that other antivirus products are detecting stuff that McAfee isn't, then you should consider switching. My guess is that unless your users are engaging in risky behavior, or like opening spam emails - you'll be protected from most common threats with McAfee.