The questions you have to ask yourself are, "How hard do I work for my money?" and "Have I really gotten a lot of practical use out of Onstar?" If you can answer No to the first, and Yes to the second, you should seriously consider renewing your subscription.
Reporting wrecks can be done via cell phone or handy road flare tossed (or shot) out the window; I don't need to pay extra to do that. Asking for directions is kind of redundant when I have a GPS navigation system. (If that isn't good enough, I probably shouldn't be driving anyway.) My car honks if I leave my fob in there, so getting locked out isn't an issue. Calling for a tow? Cellphone wins again. Car stolen and needs to be located? Not impossible, but difficult without a programmed FOB or flatbed hauler. Both unlikely for me. The only novelty service I can appreciate about Onstar is the ability to sense the airbags have gone off and have them call someone to haul me off in an ambulance or hearse without me lifting a bloody finger. (How convenient is that!?)
But is that "peace of mind" worth hundreds of dollars a year? Not for me. During ownership of three Cadillacs, the only time I've ever heard a voice on the other end of the Onstar speaker was the day it was activated. (They were very courteous.) Now, lower the price to something like XM and I might be more inclined to sign up, crash my car and wait . . . for that familiar, courteous voice that I might confuse for that of an angel. . .
Personally, I think Onstar panders toward fear to help sell the service. Read some of their testimonials; a lot of them read something like this: "Thank God for Onstar. It was dark, and my car died. I didn't know what to do! No one would help me. But Onstar cared. They sent the cavalry and saved me." If you're in Baltimore in the dead of night, with four flat tires and no cell phone, Onstar is indeed your best friend. For my money, (and I work hard for it) there are better ways to spend it. Your milage may vary.