I'm with Joe, Ithink it's more of a cool factor!!!
Ihave heard this debated before at the field, we all know how that goes, the thinking was that the four strokes were developed because of the noise factor?? You be the judge.
They do throw a bigger prop, they do use less fuel, they do produce more torque and they do sound cooler.
Other then that Ihaven't noticed much difference in flight. There may be less engine snot on your plane at the end of the day?? Now that Ihave seen it mentioned that could be right? Maybe not?? Ihave never seen a Saito that didn't sling so much snot the plane wasn't dripping when it landed, Ihave one YS that is really snotty too but that could be where I have my muffle pipes exit??
Idon't know, Ithink it really could just be the cool factor?
What ever it is Ijust really like them and don't have any plans about changing any time soon.