I've installed Wi-Fi Security on two iOS devices (iPhone 6, iPad 3), one OS X (iMac Retina), and two Windows machines (7 and 10). In all cases, Wi-Fi Security slowed network download performance into single digits, and upload performance into single or low double digits.
For example, at work, I'm on a fiber optic that normally produces the following Speedtest results:
SpeedTest before Installing Wi-Fi Security:
Ping: 5 ms, Download: 95.28 Mbps, Upload 94.98 Mbps
With Norton Wi-Security on, the Speedtest results are as follows:
Ping: 71 ms, Download 8.59 Mbps, Upload 15.78 Mbps
I get similar performance impact at home on wireless (Spectrum 100MB) and on mobile (Verizon 4G). As far as I can tell, the product isn't capable of delivering high-speed internet bandwidth. I've seen this with other consumer VPN products as well, thought not as extreme. Is this a good trade off - slow (or very slow) performance in exchange for some additional security? Not for me.