Again, 80cfm for close to $100 (if you find it on sale) and at full speed it's silent. Put it inside a cab behind a door and it's totally silent running flat out.That way, I could turn fans all the way down if someone knocked on the door.
Why worry about not being able to reach the switch before you go to the door. Total silence while maintaining total airflow.
Yes, the little PC fans can work in a pinch but if you're going to use your cab for more than 1 or 2 grows it's definitely worth it to have excellent airflow.
Peace of mind is an extremely valuable commodity and can be had for much less than people think.