Well, press is more a set it and forget it type defense .. and it causes more fatigue so you need more depth. You have no way to try to impact an individual scorer on the other team. With enough SPD, ATH, DEF on the team, you can get lots of turnovers.
With Man, you have lots more coaching options. You can double team and/or play a better defender against an individual scorer. Also, less fatigue, so your starters can get more minutes (when compared to press).
If you can get 10 players who can all play equal minutes and score with them, press is great. If there is more differences between your starters and backups, then Man is best. That is why I think really good Div-1 teams are mostly man and there are more really good press teams in Div-2 and Div-3. In Div-1, the really elite players are limited and your starts are usually significantly better than your backups for the really good teams. In Div-2 and Div-3, the backups are usually much closer to the starters on good teams, so press can be more effective there.