I wrote about using Cloak to stay safe on public WiFi a few weeks ago. A few days later, I got an email from the folks at Tunnelbear asking if I'd like to try their service. I had heard good things about it, so I gave it a shot.
Key differences between Cloak and Tunnelbear:
1. Tunnelbear is half the price of Cloak for the unlimited plan (it's even cheaper if you just need iOS VPN service)
2. Tunnelbear doesn't have the feature where it automatically connects based on the SSID being used.
Both services work well and are easy to use. Cloak's killer feature is the ability to "set it and forget it". Your choice is to basically save $50 and have to manually connect. If you rarely use a VPN, this might be a good choice. If you use it often, Cloak's automatic connection management might be worth the premium.
I've been told that the VPN backend on iOS 8 has been completely re-built, so these services should get even better.