Power up 100% or Default 50/50, which one is better?

Hi everyone, Im completely new here on steemit and trying to find more information on how the payout works on steemit.
I have a few questions?
I wants to know the difference between power up 100% or default 50/50?

which one is better between power up or default?
Is there a reference page to visit to get a better understanding of how does steemit payout works?
So please can someone help me to understand that how the payout works and which one is the best way to make and save up your money before taking a pay out.
Thank you.