Blame staff for infections more than poor value AV software
If you're going to get a virus infection then it's most likely to be one of the more common viruses. Therefore any anti-virus program is going to be reasonably effective on average in terms of protecting you. Any brand new virus can take time for AV software to receive an update to detect and resolve the infection; there will always be casualties to begin with, much like any human viral outbreak. Sad but true.
I have used AVG Free for well over a decade on many personal PCs and it's been fantastic, and certainly lets machines run smoother than the more bloaty and costly products. I pay for AVG for use on servers and it's very cheap so the value is excellent. (No infections in 6 years)
In my view enterprises should spend less on AV licences and more on implementing and policing better IT security policies for staff. Most infections are down to the ignorance or risk taking of staff - which can be avoided if staff were better trained on the subject and IT was better policed (physical and network). That sounds a bit draconian but what do you expect if staff bring in files on a USB stick to print off on the office printer, or download executable files at work, or open emails that most of us would find suspecious, or access Facebook (clicking on links), etc. This stuff should be done on computers at home or personal smartphones.
When I was younger I hated these sort of rules and I was a risk taker. But 15 years on I'm more experienced and have bigger responsibilities so this "draconian" approach helps safeguard the business, jobs and reputation. Damn, I sound l like my old boss. I'll be wearing the same sort of clothes as my dad soon too probably.