Well, I've now seen the place for myself - and I would definitely recommend a visit to anyone with an interest in reptiles. The crystal-clear underwater viewing of the large crocodiles is impressive, but the collection of smaller reptiles on the first floor is this collection's real gem.
It is said to be "the largest collection of Australian reptile species IN THE WORLD" [emphasis as shown in their guidebook]. That is probably true, though in fact they have limited the size and scope of the collection by concentrating solely on the reptiles of the 'Top End' (Northern Territory). So, for example, you won't find any tiger snakes or other species native to the southern parts of Australia. I had hoped, given that the waters around Darwin are home to various types of sea-snakes, that they might have tried to maintain at least 1 species for public exhibition but so far this isn't the case.
What Crocosaurus Cove does have is a great collection of North Australian lizards and snakes. The number of monitor (Varanus) species is amazing, and was certainly the highlight of my visit. Many taxa are kept which don't reach collections outside Australia. They include White's (Lemon-throated) Monitor V. baritji; Long-tailed Rock Monitor V. glebopalma; and King's Rock Monitor V. kingorum. Also on display was a small monitor to which they have given the name 'Blue-striped Goanna', which is believed to be a taxon still awaiting scientific description.
As well as the monitors, the collection shows many geckos, agamids, and elapid snakes. A must-see for anyone with an inclination towards herpetology.