As Mr Insa mentioned do shop around. I have had a mixture of service from the main three but in general they all deliver the goods. The RAC once left us stranded up Crown Point Road, which is a desolate dank dark and wind swept Moor, they said it was all our fault for saying Crown Point Manchester. Why would I say Manchester when I was in Burnley.
I never used them for 25 years afterwards as a metered out consumer punishment for their inadequacies but am now back with them. I received a massive discount as a package with their own insurance for £70 annually covering breakdown, relay, at home and European cover.
Breakdown cover is very much akin to gas and electric in that you have to seek out the better deal upon expiry. New custom is rewarded far more than loyalty.