GM offers onstar on 50 models of cars. The problem is most rental companies do not buy those cars. Avis used to buy them in the buick lesabres, but now only the caddys have it. Its about the same price as the neverlost feature, but you buy a "package" of minutes with your ccard, then you use the onstar feature at your will. the 911 feature is ALWAYS active in the Onstar equipped cars for avis.

And nowadays, just spend 400 bucks on some tomtom GPS system and dont buy neverlost et al.

though onstar is a nice option, they are a concierge service too, thy can very well book reservations for you, even hotels. A good use of onstar would be in cross country travel, or if you are in town on business where time is imporant.