Well this product certainly fits well into my ideal layered solution. The reason is, with Bit Defender scanning my network on Untangle Transparent using anything with the BD engine has limited returns and doesn't offer much in the way of layered defense. Since I now scan all traffic with Fortigate, FortiClient offers limited returns.. With Kaspersky Free, my network looks a bit like this;
Network (Inbound, Outbound, Lan/Wan)
Fortigate E Series Appliance (Fortinet Antivirus, Anti-Botnet, IPS, AppControl, Web Filtration, DNS protection)
FortiSandbox Appliance (APT, Zero Day, Unknown Threat Protection - REAL-TIME on-network Sandbox Evaluation)
Untangle Appliance (Transparent Mode - Bit Defender, ClamAV, Zvelo Web Filtration, SNORT IPS)
Desktops/Laptops
VoodooShield Pro (Always On)
Heimdal Pro (Vectorn Enabled)
Kaspersky Free
Rollback RX
Many other things, such as VLANs/Segregation, Bulldog AP w/WIDS and local DDOS suppression of Rogue WiFi Clients/Devices/MACs. WiFi Digital Fencing. A program that disables network adapters when the machines are sleeping. Fortinet Policies to block WAN traversal for specific internal MAC addresses during X to X hours of the night, etc.. I might have one of the most secured networks in the world to be honest.

Some of the recent additions came after carefully watching/reading folks on this forum - which helped immensely.
Anyway.. I'm experiencing what I would deem virtually zero system impact with this setup including Kaspersky Free. But the level of hoops any attacker would have to broach is pretty substantial in this case and they'd have to factor in a magnificent blended protection system, not even counting the nearly daily rollbacks.. Kaspersky adds an incredibly good layer to all of this - another set of hoops to get through.