I have been using Cloak in beta for a while now and I think it is a really nice VPN service. Their menubar tool allows fast access to privatizing your internet session — as well as a nifty feature that automatically will turn it on when you are not on a secure network.
I haven’t used it a ton, but when I have needed it the service just worked and worked very easily. Their plans are pretty reasonable, including a nice free plan that only limits you to two hours a month.
They also just released their iPhone app — which makes using VPN on iOS just as easy as their app for your Mac.