I don't really think of it as a "qualification". To me it's just a more complete OW cert, but it's still just basic OW stuff. I feel like the first course that takes one to a new "qualification level" is rescue diver. This, of course, is all just IMHO, and you know what that's worth.
But a lot of folks get really heated about being "advanced" or not advance OW, and arguing about how many dives you "need" before doing it. If you just look at it as a longer basic OW cert and not really a "qualification" level, all that arguments kind of evaporates.
When I got certified, my instructor sold it that way. He said, "Look, you're not going to take your skills to a great, new level with AOW, you'll only do that with a LOT of dives and then taking Resuce diver. BUT, what AOW is good for is building your feeling of personal confidence and comfort in the water, and that will make you a little bit of a safer diver. Anything that makes you more comfortable and skilled in the environment is a good thing. Plus, you'll feel better doing your first night dive, your first deep dive, your first whatever dive, supervised. Most new divers are a little tentative about their skills right after BOW cert, and this gives them a few more dives with an instructor so they realize, hey, I can do this! I recommend you do it as soon as possible, but don't think it's going to make you an "expert" or anything like it. And be sure to never do anything technical without further classes that really do expand your knowledge and training."
I thought that was a reasonable explanation about what the AOW is supposed to be. . .and a very good argument for not waiting until you have a lot of dives before doing it. I was lucky enough to be stationed on the beach in the Philippines at the time, so after my OW cert, I did several easy shallow day-time dives, and after about 6 or so, signed up for the AOW. He was right, I felt a lot better about doing the deep and night dives in a small group with an instructor. A lot better. And he was also right, I felt more confident in my skills. It was a great way to do it. I went right to AOW in about 15-20 dives in a 3-month period.
Now, mind you, I'm a careful individual, I don't do stupid stuff, I'd get an instructor and take another course before I'd even poke my head into a wreck or even think about an overhead environment dive. I'm not a macho kind of guy who thinks the AOW made me a better diver. All this is a function of diver personality makeup, not the AOW course. But I highly recommend doing the AOW as soon as you feel like it after BOW cert, the earlier, the better. But don't assume it makes you anything other than a basic open water diver.
In the interest of full disclosure I am not an instructor and this is just my feeling about what AOW is or how it should be viewed, and there are a whole lot of "better qualified" opinions around. But I think getting new divers to do more dives and more varied dives with an instructor in a learning setting is much better than asking new divers to hold off on doing the AOW. I'd rather the BOW and AOW were combined and it took ten dives to get a BOW cert, that's kind of how I feel about it. But it would cut down on the number of certs immensely. Do the AOW, but don't get cocky about it what it does for you, says I.