There are various levels with RAC - what's the claim limit, how many claims can you make in a year, what's excluded etc. Is it free? Gift horses' mouths etc.
I had one with my DB7 that paid a maximum of 1000 per claim - when the coils went, it wasn't good enough, though it certainly helped! Conventional wisdom says the only good warranty is the AM warranty, nothing gives peace of mind like a proper pre-purchase inspection though.
RAC Warranty example - DB7 Vantage coil pack went. Analysis of the problem, 3 coils of 12 have gone. So RAC paid for 3 coils. It was explained to them that the others would go imminently at another 6hrs labour just to get to them but they would only pay for the three, I had to stump for the other 9, plus plugs, plus the catalyst that had been fried with unburned fuel. Had AM warranty been on there, they would have know it was cheaper to replace all 12 coils and save the double labour.
The fact that the selling garage, Marcos Fothergill, categorically stated (and wrote in the service history) they had done the coils before I bought it, a total and utter fabrication as it turned out didn't seem to bother anyone. Even a solicitor said I had no chance of getting anything out of a used car dealer. Bitter, me?