Another major concern with VPNs is speed. In general, using a VPN is going to increase your latency (or your "ping"), and decrease the speed at which you upload or download data. It's very difficult to say definitively which VPN will have the least impact on your browsing, but extensive testing can give you some idea which service is the fastest VPN.
To prevent middle-man access and to ensure that the data is sent via a secure tunnel, certain criteria should be met. The criteria include a DNS Leak Protection (over IPv4, IPv6 and WebRTC), encrypted traffic via a Private tunnel, and hopefully no logs of the data saved anywhere. However, if the government wants to see which websites and web locations a user visits, the ISP provider can demand and get that information. Thus, no real anonymity is achieved, but the specific data will be encrypted, secure and free from middle-man attacks.
To narrow the hundreds of VPN providers down to a manageable list, we first looked at reviews from dedicated sites like vpnMentor and TorrentFreak, research and recommendations from noncommercial sources such as That One Privacy Site and privacytools.io, and user experiences and tips on various subreddits and technology-focused websites like Lifehacker and Ars Technica. We settled on 32 VPNs that were repeatedly recommended. From there, we dug into the details of how each one handled issues from technology to subscriptions: