As a new diver, I was originally planning to get my OW cert, then take the AOW class a few weeks later. I wanted to dive nitrox (I have a friend who dives nitrox) and they were offering that, rolled into an AOW class, something like two weeks after I got my cert for OW. Turns out, my parents decided they didn't want to pay for it (classes were a birthday present). Looking back on it, I'd much rather use that money to go diving with. I don't need and AOW card to say that I'm a good diver, I need to show that I'm still alive after, say, 500 dives. I don't think I can get rescue diver cert before I get AOW, but I'd rather have rescue cert. than AOW.
As an aside, I took the PADI textbook home to learn for my OW cert. Had to asnwer some qustion and take the test and go to the dives and I was certified. The reading was easy, I highlighted all over the place in that book!! I read most of it twice. At the first pool dive, the two girls that took the class at the shop were all like "oh, we'll have to show you how to set your gear up" At that point, I had alrady taken and passed the final exam. I had my gear setup twice as fast as they did. (this was a trend that seemed to continue throughout all of our dives) I felt I was much better prepared for everything (except that adrenaline rush that comes when you realize you can breathe underwater) because I had already read the book, taken the tests, watched the videos and everything before ever getting inthe water. The instructor was pretty good about going over the stuff I missed on the quizzes, he'd explain it and made sure I understood it better. I explained a few things to him too (he had gotten the whole displaces more water than it weighs then it's positively bouyant thing backwards)
The education PADI gave me was ok. Because I studied everything better on my own, I feel I got better than if I had just done waht PADI recquired. The evidence of this was my dive experience compared to the other students, who just showed up and did bare minimums. I was in the water faster, packed up faster. My gear was cleaner at the end of a dive (no silt on everything). I did not have problems with regs freeflowing, masks flooding, or underwater navigating. I never panicked underwater and headed for the surface. (perfect example of a panicked diver: spit out reg at 10 feet down on a line, headed for surface, MOF.....instructor had myself and the other girl chill and explore while he worked with the other girl. Anyways, I feel PADI does an ok job, but if you want to be really good you have to take your education into your own hands.