That VPN comparison site is great. However, an important facet missing from the spreadsheet is whether or not there is a "kill switch" for their service. A "kill switch", when enabled by the user (check box or such in the app’s Preferences), disables all internet access for the computer if the VPN connection fails, thus avoiding IP exposure and exposure to your ISP in such a situation.
Tunnelblick, commonly the only way for Mac users to connect to a VPN service's OpenVPN protocol, does NOT have a kill switch.
For Mac users I'd recommend getting a VPN service that has a dedicated Mac connection app with a kill switch.