Good Question.
I was here (Hive/Steem) in the days of 75/25 and a variety of timing/reverse auction/double payout/linear vs x2 rewards curves... and my primary vote in favor of 50/50 (and I'll add that I was skeptical for a long time!) is based on the fact that it encourages content creators to also be content consumers, which in turn helps drive engagement within the community. And an engaged community tends to be a stronger community that finds it easier to attract new members and thrive.
I think it's important to apply "Big Picture Thinking" here and not just think about who gets rewarded, but what kind of image will a given reward system portray to someone external to the community who's debating whether or not to become part of the picture.
Yep...what he said