I have the Honda used car extended warranty on my Civic Tourer. In the last 9 months since I purchased it at 4.5 years old, it's had a new air con compressor (£1600) and a new rear seat locking mech (£170). So in my experience I'd say it was worth the £295 per year (or less if you bulk buy a few years). But equally, other people may have found no need for the warranty.
Honda's website says cars up to 8 years old can be covered, but the service department told me they would cover it up to 15 years old if it's had continuous warranty and servicing through them in that time.