I did the dive a couple of months ago and had a fun time, but would probably not rush back to Orlando specifically to do the dive again. I've also done the dive in the Georgia Aquarium in Atlanta and it is much superior (but also much more expensive). I consider both dives to be 'bucket list' types of dives: glad I did them, but would not rush back anytime soon. Then again, I live near Jupiter Dive Center and have world class drift diving 10 minutes away from my neighborhood: during the dive quest dive, I found myself getting just a bit 'bored' since there is only so much to see in somewhat smallish the tank: I don't recall having the same feeling after my experience in the much bigger Georgia Aquarium tank (which also has whale sharks, manta rays, more types of sharks, etc.) I am sure that if I didn't get a chance to dive as often as I can in the big water off of Jupiter and West Palm Beach, I would have been really impressed with the Disney dive. Also note that if I ever find myself bored out of my mind at DisneyWorld (I've been to the park at least 30 times) with some relatives from out-of-town and could find a spot in a dive quest dive, I'd probably do it again.
If you do the dive, make sure a relative takes some pictures or videos from outside the Epcot tank.