Nope, I never assume. You know what they say about that.....
Look, everybody has their own opinion, for their own reasons. But, as has been mentioned already by other members, it all boils down to the instructor. At the end of the day, a safe diver is a safe diver.
Still, you miss the point. Let me give you an extreme example. I teach a Scripps Model 100 hour course. Due to the exercises we do, the way in which we do them, the number of dives and the order that we preform skills, the course I teach could not be offered within the PADI framework. There is no PADI course, or progression of PADI courses, that approximates our content. I will stack the product of our course up against any level of diver in the PADI progression (including DM and Instructor) and I am confident that the knowledge and skill level of the 100 hour student will, in almost all cases, meet or exceed that of the conventionally trained individual.
So ... is this the result of the instructor, or is it the lack of the limitations that PADI imposes? In reality it has to be a combination of the two, but I maintain that we could not produce divers with the knowledge and skill level that we require if we had to operate within the limitations of the PADI curriculum.
So dial it down a dash, the "standard NAUI course" (there really is no such thing) has run about 36 hours historically and includes a fair number of things that are not to be found in the PADI cirriculum.
The point is that that while all PADI programs are virtually identical, all NAUI progams are not, there are NAUI programs that are no better than the typical 18 hour, two day PADI couse and there are NAUI programs that run 100 hours and include 16 dives, with the "average" NAUI program running about twice as long as the standard PADI couse. So comparing a NAUI program that is run on a PADI model, something that some cross certified Instructors do, and NAUI permits, is not really a fair comparison of what the differences between the two agencies are, it's just a demonstration of the fact that NAUI has been forced to reduce it's minimum standards to a point that now there are just barely above PADI's maximum standards.
As to a "safe diver" being a "safe diver," just look at the
Divers Down watch out! thread.