Marti,
Yes, you have to be a complete bag of sh*t to not get promoted in the AMDO community. Also, orders are picked out of OCS, and timing/luck is everything. For example, there were 2 AMDOs in my class, and there were only 2 billets. VS-33, and AIMD Stennis. So getting a VP squadron is a total crap shoot. To give you an idea, school classes up 4 times a year, and I think we had such a limited choice because we were commissioned in December, and school was in January. They guys commissioned in October had a chance at our billets, plus the ones they ultimately chose.
Second, if you're in port with a squadron, there are planes. The aircrew still needs to fly to keep quals up and what not. Being underway just means a longer workday, it's a little less busy back at the beach. I can't really compare my job to supply, I currently have a supply job persay, but I will rotate most likely to Assistant Maintenance Officer next. If I were in the Supply Corps, all my jobs would be in supply. To be completely candid, I specifically did not want to join the supply corps, and ironically, my first job in the squadron deals with supply. Oh well.