I just got back from WDW and my friend and I did DiveQuest last Thursday. It was amazing! Yes, it's on the pricey side, but (contrary to what I thought) all the money goes toward the Disney Wildlife Conservation Fund.
We did the 4:30 dive (there's also a 5:30 dive), which is what I was told the better one. You meet 15 minutes early outside of the park next to Guest Relations. From there, the group is escorted backstage. After about 45 minutes of touring the Living Seas, you suit up and get ready for the dive. We were marched around inside before the dive so everyone saw us suited up.
We were in the water for about 45 minutes. The feeders are in the tank at 4:30 and get out right before you get in. There were plenty of fish and rays that were expecting me to feed them and came right up to me waiting. You take a short 15-20 minute tour of the tank and then break off and get to do whatever you want. Yes, the fish are amazing and being able to swim next to a 10 foot long shark and a thrill, but what I think was the best part was being able to go interact with guests at Coral Reef and the observation windows.
There is a video recorder in the water with you for about 20 minutes who records the dive. If you have friends or family watching you, the recorder will film you and your friends/family interacting with you. The DVD is $35 and the money also goes to the DWCF.
After the dive, we cleaned up and watched the video with our friends and family. The CM who was in charge (ours was Mike from Ohio...very funny guy!) goes through The Living Seas and collects everyone who knows the divers and takes them backstage. You get a nice t-shirt, certificate, DWCF button, and a stamp in your dive book. If you forget you book, they give you a sticker that you put all your info on that they stamp so you can just stick it in your dive book.
We were out of The Living Seas about 7:15. Mike escorted us to the new Nemo ride and got us to the very front of the line. Not everyone did that...without it, we would have been out at about 7:00. It was an amazing dive and I highly recommend it. There are a few discounts that you can get (if you book with a Disney Visa, if you're military, I think if you're an AP holder). I found out about the discount after I booked on wdwinfo.com and called them back and got my military discount. I saved $21 a person (I think....hmmm....). Anywho...hope this helps!