This is a Bear Polar It would seem as if in this day and age of fancy single cam bows that the old round two wheeler would not be useful any longer. Two areas they excel at are target shooting, where speed is a very low priority and for the finger shooter who likes the smoothness of there draw and a longer axle to axle length. One other area they are good with is limb materials. The two cam bow was a vast improvement over the round wheel bow. It allowed for all things being equal a faster arrow to be launched with more energy.
Faster arrows mean flatter flight path to the target and fewer range estimation errors.
Now a days most moderate priced bows are of the two cam design. Two cam bows do have some disadvantages though, they are more difficult to draw back and they have more shock when released. With the newer designs of cams though the shock has been reduced greatly. The design of the cam is what determines how much energy is imparted to the arrow upon release. Look around and you will notice there are as many differant designs of cams as there are trees in the forest.