Some pilots at 500 hours have the situational awareness, ability and confidence to not only make it through training but safely and professionally execute their duties as First Officer (up to and including commanding the aircraft if the PIC becomes incapacitated). Other pilots at 500 hours lack that ability.

We'd all probably be better pilots if we had 500 hours of night freight in a Baron or Navajo, then 1000 hours in a 1900 or Jetstream before transitioning to a small jet...but you don't have to have that background to do your job safely and do it well.