Seems to me the original post was based on the idea that someone with OW wants to advance his training and be allowed on a wider range of dive boat excursions. GUE Fundamentals seemed to be a great way to do the former; an AOW cert. seemed to be the way most people do the latter. So he wondered if he did the former, could he do the wider range of boat trips, or would he have to pick up AOW just for a 'dive trip > 60' license' (practically speaking; I know it isn't literally).
I suppose the topic wandered a little into ways to pursue the original goal. From what I understand, some ways:
1.) AOW with a teacher who adds a lot to the course, or teaches it very well and to unusually high standards.
2.) AOW + further training, such as technical diving pursuits.
3.) AOW + a lot of self-directed practice, or mentored diving.
4.) One of these Tecreational classes.
5.) The ADP program, which is evidently very different from an AOW program. Which raises the question of whether one gets an ADP cert. that will be broadly recognized on dive boats, especially since a lot of diving is done outside the U.S.
6.) The Naui Master Scuba Diver program, which was originally intended to instill instructor level knowledge & skills minus the teaching component, which I'm surprised hasn't been mentioned (at least that I've noticed), and it much different from the 'master scuba diver' cert. requirements for PADI & SDI, for example. It's an actual course in and of itself.
For the intermediate (or ambitious beginner) diver looking to progress, how would you guys 'stack up' these options? What additional options did I miss?
Richard.