Antivirus for small Office

Hi Community,

What antivirus provides the most punch for the money. We are a small office 10 or so PC's that need a license - i dont want bloatware but something that can protect our pcs without getting in the way of operation.

Please let me know you thoughts, experiences and what ultimately would be best - btw we run pc's from vista to windows 8 so it needs to be backwards compatible.

AV software alone will not be enough, you will need anti malware/spyware too
My company offer me some ****** av software but i didn't use it.
Currently i'm using Bitdefender Internet Security 2015 for both my home and work pc, it's easy to use, powerful and light
http://www.ebay.com/itm/Bitdefender...292?pt=LH_DefaultDomain_0&hash=item4ae5208004

and this at a anti spyware/malware.
http://www.ebay.com/itm/Malwarebyte...316?pt=LH_DefaultDomain_0&hash=item3cf324c26c

I like Kaspersky. You can go to http://www.av-comparatives.org to get unbiased results on the different AV products.