A very recent purchase, it has improved my economical driving efficiency dramatically. It advises the best gear to use and indicates in red if you accelerate to rapidly or brake to hard. My first day efficiency was 85%, this has improved daily and current average efficiency is running at over 95%! You can select the model of car you drive and you can change the car characteristics very easily if you drive more than one model. I have used it in two cars so far, an Audi and a Kia. It is a simple matter to switch from one car to another. The satnav performs adequately, and is superior to the Navigon I previously used. This unit is certainly not a gimmick, and will ultimately pay for itself in fuel saved. No other satnav has the potential to pay for itself. So its green and it gets you there. Highly recommended.