AOW requires having a very good instructor (sounds like Divedoggie is your best bet) who doesn't just take you on the five dives. Since there is no EXAM, it is fundamental to get that one on one time and dedication from your instructor.
If you find this instructor, AOW will give you more confidence in your diving and make you enjoy the dives more because you will be more in touch with what's going on around you and you will be more alert yet more relaxed at the same time.
I agree, I took AOW right after OW from the same instructor, in whom I had confidence. We did all of our dives in Lake Travis, which is just a giant, deep mud pit.
Since there was exteremely low vis 6'-5', we were challenged. We had to really learn navigation (I had to repeat it twice to pass). And since the water was deep and the vis was bad, we worked mostly on skills.
We had several situations arise, that down the road made me feel much more confident, we lost buddies, our way, had to abort a couple dives for ear and equipment problems.
Mostly I gained confidence, from the knowledge and skills learned and improved. We were also exposed to multilevel and computer diving. All this makes me much more comfortable in the water, I understand better how to act in a situation, rather than burning all my air panicking, and I generally enjoy my diving.
You can never have too much training, and you can't have too many dives, you get both with AOW. As for taking the class on vacation...I was really worn out after taking the class, and working on the skills, I don't think I would like to waste my vacation working like that (But I will dive 'til I drop smoetimes).
Good luck.
Danny