I just got back from Kona where I took my AOW training, and I am glad I did...
I had never been diving in the ocean or off a boat, and the AOW not only offered instruction, but it gave us an instructor all to ourselves for the first five dives of our trip. Our instructor had an insane skill level, I swear she was actually a fish, and she was able to show us what she was doing and how she was doing it.
We did the course work ahead of time, and she went through the reviews and over the materials before each dive, to make sure we really knew the stuff and weren't just filling in blanks. Then we made the dives, and worked on the stuff that we needed to improve on.
We ended up doing deep, boat, night, navigation and buoyancy. Of the classes, I think by far the most important one was buoyancy... we did it third (our second day there) and it really, really helped with the rest of our weeks worth of diving... it wasn't just the techniques, it was the feedback from the instructor on how to improve that helped. I saw a video of me diving later in the week, everything was streamlined and trim, I was horizontal, using breath control to move up, around and through the coral beds without touching anything and with my hands tucked properly and I was like "Whoa! That is me?".
The only "silly" class we took was "boat diving" but, you know, we were on vacation and on a boat. That class was a bit different than the others, since a lot of it was taught by the boat captain (also a certified instructor) who not only showed us the basics, but also taught us how to identify good looking dive sites by the color of the water, how to deal with currents and surge, how to recognize dangerous areas to stay away from through the champaign (etc.) so it didn't turn out to be as donk as I thought it would.
The AOW I took wasn't NEARLY as intense or complete as our initial training was, but rather it was kind of like an "introduction to specific kinds of diving".
It was nice to have an instructor with us for our first 5 open dives (actually she stayed with us through 8 dives since business was so slow and we are good tippers
) since we are NOOBs, but we did actually learn some stuff.
Navigation is too easy at Kona the way the AOW testing system is set up. With 100+ ft visibility, it would be WAY too easy to cheat if one had a mind to.