sevenx - I've been very happy with my AJ. The layout of the boat is pretty unique - it's got plenty of room for serious fishing, and also seats 8-10 or more for afternoon or evening booze cruises. Thanks to the beam of the boat, the cabin has a lot more room than you'd expect from looking at the boat's profile. When the V-berth is filled in, the big end is as wide as a king-size bed. I'm not suggesting you'd want to live aboard, but wife, infant daughter and I took a 10-day cruise. I don't dive but I'd think it'd be a pretty good dive boat - friends have told me they've seen some being used as dive boats in the islands.
One of the best features of the boat is also one of the worst - the level cockpit and engine boxes make moving around great, but the low profile means she takes more spray over the bow and windshield than many other boats her size.
Build quality - it's not a Bertram or Blackfin, but I had her surveyed for insurance company last year (because she passed 10 yrs of age) and the surveyor wrote in his report that the boat was "extremely heavily built for a boat it's size". I've always been impressed with the heft of the hardware - when I called the factory to get some info when I re-propped a couple years back I learned the 31 AJ was the smallest model built at that particular SeaRay plant. (so they used the same hardware that's on some much bigger boats)
Mechanicals - there's not much to go wrong with straight I/B setup. With the exception of a couple of the sparkplugs, it's pretty easy to get at everything - thanks to the raised engine box design I mentioned above. I don't know how bellsisland compares this boat to something with V-drives - maybe you're thinking of the current 29 Amberjack, Dean? My boat has carbed 454s; I cruise around 24-25 kts at 33-3400 rpm and burn about 25 gph total. Any faster and the 4-bbls open up and you can almost watch the fuel gauge move.
Don't know where to stop - if there's particulars I haven't answered let me know here or feel free to e-mail
sr31aj@yahoo.com. I'd be happy to send my phone # if you or your buddy want to chat.
Don
Searay Amberjack 31' 1992 opinions? 
