I rented a Ford C-MAX the other day. It's Ford answers to the Prius, but with much more power and much lower fuel economy. It's a very nice vehicle, although I much prefer the simple and sparse aesthetic of the dashboard of the Prius. One feature of the Ford is an almost photo-realistic graphic of leaves, a feature that the user can chose to display to the right of the speedometer. As you drive more efficiently this "Efficiency Leaves" game will add leaves to the picture. As you drive less efficiently, leaves will gradually drop away. The challenge with this attempt to graphically show your efficiency is that in choosing a realistic image of a branch, Ford also kept to the random appearance of a natural tree. Consequently, it is very hard to understand at a glance how well you're doing. It's not obvious whether your tree is full of leaves, and therefore that you're winning the efficiency game, or whether your tree is sparse.
Contrast this with the Fitbit which uses a less realistic image to represent progress. After a few minutes of use, it's quite clear how large you're growing your plant and therefore how much progress you've made.