Are there any special features that would distinguish a good dive watch from a great dive watch?

While a dive watch is loaded with valuable features, two features in particular would separate those deemed as good from those watches considered to be top of the line - a rotating bezel and level of water resistance.  A watch with a rotating bezel on the face will include a pointer indicator allowing you to align the bezel with the minute hand.  With that, as you descend the bezel would not move allowing you to easily determine the amount of time spent diving.  In addition, the water resistance level tells you how deep you could dive without damage being done to the watch.