I use cruise as a novelty in UK but rare I can use it without having to disengage it every minute. Even with average speed areas where it’s most useful. People in front just aren’t keeping bang on one speed.
Diving across US though, road that stretches for hundred miles, set cruise, relax 😀
France’s autoroutes work with cruise control also as rarely see major amounts of traffic.
Anyway, second hand from a dealer, the main thing I’m looking for with a dealer purchase is that it’s been properly serviced, is safe, they’re not hiding something that’s broken or needs doing, and most important of all I get a decent warranty.
That said the warranty tends to be an aftermarket one, not manufacturer and found in the past there are a lot of exclusions.