I did it in May, as a Mother's Day present. My favorite part was being able to see and wave to my kids; after I got out, my daughter said, "Mommy, you were dressed up just like a scuba diver!!" I also enjoyed the tour, and the other divers I met. (Shoutout to Marie!)
What I liked least: I couldn't get my bearings about where I was supposed to be for the camera, so I missed out on one of the times everybody should have been in the video. Also, there was something anticlimactic about knowing exactly what we'd see, how many of each species they had. I guess I like being surprised by what I see in the wild.
All in all, though, it was a good time.
By the way, if you have a Disney VISA and
DVC, ask which gives the bigger discount.