I have used the free version and decided it to give it try for paid subscription. I dont see any difference in the speeds. Biggest downfall for this VPN is going in a sleep mode or just not active during phone in a sleep mode. If you use VOIP apps for calls, this is not the VPN. By the time VPN is connected again, the call will be dropped. I have to leave the VPN off in order to receive calls. It takes longer to connect compare to other VPNs during sleep mode. Ping time increased by 5-15 millisecond during multiple speed tests.
dube101 about ZenMate VPN & WiFi Proxy