Just to add.
If you have a lower powered car doing 70 on the cruise, you come to a hill and the car attempts to stay at 70 with the cruise flooring it and using loads of fuel. The same car driven without cruise, the driver would use a little more throttle but accept that he/she will slow down a bit up the hill.
A higher powered car on cruise at 70, comes to a hill, the cruise tickles the throttle a bit more and keeps it at 70 by using just a tiny bit more fuel.
Higher powered and torquey cars (diesel ones) get better MPG on the cruise at 70. 1.2 petrol cars get better MPG round town.
Horses for courses.
If you have a lower powered car doing 70 on the cruise, you come to a hill and the car attempts to stay at 70 with the cruise flooring it and using loads of fuel. The same car driven without cruise, the driver would use a little more throttle but accept that he/she will slow down a bit up the hill.
A higher powered car on cruise at 70, comes to a hill, the cruise tickles the throttle a bit more and keeps it at 70 by using just a tiny bit more fuel.
Higher powered and torquey cars (diesel ones) get better MPG on the cruise at 70. 1.2 petrol cars get better MPG round town.
Horses for courses.