The results produced from the two renderers look different, which means that it isn't a proper comparison becuase they are not doing the same thing. One of them has to be taking shortcuts somewhere, but since I rarely dabble in rendering, I don't know which one is more realistic. Which ever one is more realistic should be the winner here, not the one that is fastest.

Its like comparing a two-year-old kid drawing a tree to a trained artist drawing a tree. They are both recreating a tree, but the kid is faster than the artist because he draws a line for the trunk and a circle for the leaves up the top, unlike the artist, who is painting every little detail...