After a quick look through my zoo list I would estimate that I've seen approximately 50-55 different zoos with gorillas, with some of those facilities having more than one exhibit for the species and so perhaps 60-65 individual exhibits. I have found that the great ape species with the fewest excellent enclosures would be orangutans, and by contrast there are numerous impressive gorilla exhibits in many American zoos. I would say that Saint Louis has a very good gorilla exhibit that would perhaps be in the top 20 of the enclosures for this particular species that I've seen in my lifetime. In fact, Saint Louis has above average exhibits for gorillas, chimps and orangutans...which is no surprise considering that it is arguably one of America's top 5 zoos.