fnfalman
Contributor
If you've been NAUI certified before, then go PADI this time. That way you have two cards from two different agencies. 
Yes, Jim is correct about latitudes given to the instructors by the agencies, but really, at the end of the day, PADI/NAUI/SSI curricula for Open Water certification are extremely similar.

Yes, Jim is correct about latitudes given to the instructors by the agencies, but really, at the end of the day, PADI/NAUI/SSI curricula for Open Water certification are extremely similar.