Matt, no they do not. Just because PADI, NAUI, and SEI have an AOW class, never assume they are the same! Truth is that the differences in class structure, knowledge, and skills can be vastly different. To a large part the instructor does make a difference but agency standards also play a huge role in what you can get from a class. The higher the standards of the agency and the instructor the more valuable the class is likely to be.
My AOW class for example is not for everyone. I didn't intend it to be. I developed a class for divers who wanted actual new skills and knowledge beyond any agency standards including my own primary agency. The options for dives in the class are highly limited and only those that I felt would most benefit the student in the types of dives they would be likely to do with the card I gave them. I also developed a 6-8 hour classroom presentation, student guide, equipment recommendations, and entry requirements. It is also a pass or fail course. Certification in not guaranteed, training is. You earn the cert.
When I looked for an agency to allow me to offer some specialties that SEI did not have and that I did not have time to write myself I chose SDI/TDI. The reason being is that they have their roots in technical diving and I felt that the philosophy they have was similar enough to SEI and my own that there would be no ethical or moral conflicts with teaching their programs.
I'm still going through all the materials for the classes I plan to offer and am finding more and more things that I like.
Another thing you need to consider is that while many agency classes do crossover and you can seamlessly take one class from one agency and then one from another you can't always do this. For example take OW followed by AOW. I came up through the PADI system and took AOW two weeks after OW with only 4 dives in between. This could not occur with my AOW class. PADI OW alone does not meet the prerequisites for my AOW class. Nor does SSI or even SDI. The only agencies I will accept OW divers from with the minimum of ten dives after OW is NAUI, CMAS, BSAC, YMCA, La County, and IANTD. There may be others but those are the ones I am familiar enough with their standards to be ok with the entry level classes. The others for the most part do not teach to the same level I do in my OW class and fall short in the skills and knowledge I require a student to have prior to entering the class. Some old school PADI instructors still offer the same kind of instruction they did years ago and don't buy into the watered down versions and those divers I will also accept.
So for many divers I need to conduct an interview, set up skill evaluation sessions, remedial training, and in some cases tell them they need to get a few more dives in before they can enter my class. The reason is that the skills I teach and require are new, require a very solid foundation in basics, will task load the student to a greater degree, and if they are lacking in basic skills they will likely not make it through without getting frustrated and losing focus. That said no one has ever failed my course as I set it up so that students will succeed. I make sure they understand that these are the things they need to do before coming and they do it.
The course is arranged so that each dive is the foundation for the next. There is a natural progression in skills and knowledge that if achieved on the previous dives pretty much guarantess success on the next one. The only real way to fail is to get separated from your buddy twice or ingnore safety rules and guidelines more than once. Do the latter and the class is immediately over for you and no cert is issued or refund given.
I have set the bar pretty high for myself and my students and the agency allows me to do this. Some agency's standards do not allow instructors to add to their curriculum and test on those conditions as a requirement for certification. Mine not only allows it but requires us to do it wherever it will benefit the student. The agency does not certify divers. The instructor does. All the agency does is establish guidelines, produce materials according to those guidelines, and print the card.
The instructor decides who has earned a cert and who perhaps has not. That is the way it should be. As a student with my name on your cert card your knowledge and skills are a direct reflection of me first. Not of the agency. I take that very seriously and very personally. So I do everything to insure that the student is someone I want people to look at as an example of good training. I do everything to insure a love of the sport so people keep diving on a regular basis. I really do not want to train the person who plans to do a couple dives a year only on vacation. It is the rare diver that can do this and stay sharp. I want to train the diver who will look at nearly any body of water and say "hmmm, maybe I can dive that" and then try to.