You get only 300MB traffic allowance per day, for instance; performance isn't as good; you can't choose from as many servers; and while browsing works just fine, there's no support for email clients, games, VoIP, music or video streams, amongst other traffic types. SecurityKISS worked well with basic browsing in our tests, though.
SecurityKISS: A Free VPN Software For Windows Jul 03, 2013 SecurityKISS VPN Review - VPNanswers.com May 10, 2017
SecurityKISS vs ButterflyVPN Router 2020 Comparison
Securitykiss [F] [P] [-L] [$2+] [2/5/0.7] [O openvpn; l2tp https://securitykiss.com. Executive summary: Free option 300MB/day - I tested it using openvpn for a few days from Sydney, Australia to their LA test server and got usable speeds although as expected slow (~200ms) pings over the transpacific cable so useless for gaming I'd guess. SecurityKiss: Névtelen böngészés 300 MB ingyenes napi
You have to keep in mind, though, that as a free user you do not get access to the SecurityKISS dedicated and fast servers; therefore, your streaming will not be top-of-the-line. The speeds rarely reach 100Mbps, but the data limits are generous compared to most other providers at 300MB per day and a whopping 8.78GB of data every month.
SecurityKISS VPN Review – 2020 | BestVPN.org Jan 03, 2020