If I am not mistaken, the Stingray experience in the Bahamas is nothing like Stingray city. Maybe someone that has done both can clearly describe the differences.
I do know that the Grand Cayman Stingray City, is NOT a park, zoo or other "aqualife" type of refuge or anything. NO fences, pens or anything. It is just an sandbar area that the Stingrays have become acustomed to visiting for food. It is Fabulous, wild, and not to be missed.
Now, when it comes to the water depth, that really has to do with the day/time/weather. I have been there 3 times. The first time was the best. The water was waist deep, crystal clear and there were MANY rays to feed, hold and take great photos of. The last time (last March) there were sooooo many boats there, everyone was on top of each other. The water was a little rough due to some wind, BUT the water on the sandbar was only about 8 inches deep. This in turn had all the kids running and splashing each other and tackling each other and the water was extremely stirred up and the rays stayed out on the deeper water (5-8') and there were fewer than the other two times. I think all the kids running and splashing kept them at a distance. It wasn't nearly the great/cool experience of the previous two times.
That being said, you should definitely do it at least once.
Mrsfuzzmo