I kinda wonder what the "immediate access to information and diagnostics for your vehicle" thing is. Because nobody that's ever tried the myvolt website would ever think it's worth ten bucks a month. Even the MyChevrolet app only actually reaches the car about half the time for me. That's fine for a freebie incidental service that rides along with the crash response and stolen vehicle assist, but anyone getting billed for that kind of performance would be livid.Hard to compare plans but I just looked at OnStar a minute ago. Here are some monthly cost.