Well, similar to a degree. I have found that the NAUI courses are more comprehensive then the PADI courses I have seen. I took the NAUI nitrox certification exam today (not hard, got one of 50 wrong due to a bubbling error). One of the other people in the club decided to do it via PADI. Since the instructors could do both they did the PADI cert for him. His course and exam did much less math and relied more on the use of a computer.... This is way off topic I am stopping now.
I am a big fan of NAUI, but go where the money takes you.
There are two ways to look at it ... from the perspective of a business and from the perspective of someone wanting to purchase that business's product.
With respect to the first, going with the most recognized name brand has certain advantages ... people tend to buy what's familiar and most readily available. How the product compares with similar, less well-known offerings is generally an afterthought for the majority of buyers. That's why companies like McDonalds, Walmart and Microsoft tend to dominate their respective markets.
With respect to the second, the most important difference in skills is that NAUI requires rescue skills at the OW level, while PADI does not ... specifically, bringing an unconscious diver to the surface. But to my concern, the primary difference between NAUI and PADI aren't the skills they teach, but the approach they take to teaching. PADI's approach is very standardized, which appeals to a lot of people but ignores the significant differences in environment that really require different emphasis in order to produce a diver who's capable of diving independent of supervision. PADI's expectation is that the diver will then immediately up for "Part II" of the class (AOW) in order to gain more experience. NAUI takes the approach that the instructor knows better than the agency what curriculum needs to be emphasized ... and how ... and therefore only provides a framework upon which to build a class. They don't just allow ... they expect ... the instructor to tailor their curriculum around that framework and to fill it in as needed to apply to the conditions in which the training takes place.
In both cases, it still boils down to the instructor ... because an instructor who looks at the minimum requirements as a "floor" will find a way to turn out self-sufficient divers within the agency's standards ... while the instructor who looks at the minimum requirements as a "ceiling" will only teach what they have to ... and will produce divers who can barely function as long as nothing goes wrong, and depend on someone else to take care of them if it does.
I think the perception that NAUI's class is more comprehensive comes from the fact that their approach tends to attract instructors who take the "floor" approach to standards ... because the agency actively encourages that approach. PADI's approach allows it to some extent ... but they don't really encourage their instructors to add material above what the standards require.
... Bob (Grateful Diver)