I've been going back and fourth on the San Diego vs Omaha debate for a while now. When I recently posted my rankings of North American zoos I've visited thus far, I put Omaha at number one and San Diego at number two. However, both zoos are so close in my mind that I genuinely cannot say one stands out over the other - although keep in mind I have not seen San Diego's Wildlife Bascamp yet. What I have come to realize however is that these two zoos are great for completely different reasons.
Omaha has a far better standard of exhibitry than San Diego especially when it comes to larger animals. I can say without question that when it comes to elephants, giraffes, rhinos, antelope, zebras, lions, tigers, cheetahs, (sloth) bears, and takin, Omaha absolutely crushes San Diego on all fronts. Omaha has exhibits that could be argued as the best in the country for all of these species. Meanwhile, besides the elephants, San Diego keeps these species in accommodations that are pretty mediocre. Omaha also has an astronomically more diverse array of aquatic life and Madagascan species. I must also add that the attention to detail for both animals and guests is easily the greatest of of any zoo I've been to, as evident by the millions spent in quality of life upgrades. While there are still flaws - there still too many small exhibits in the Lied Jungle and Desert Dome that need more appropriate residents and the Madagascar building is seriously second-rate - for a zoo of this size it's about as close to perfect as you could reasonably ask.
Where San Diego fails in consistent exhibitry, it makes up for in its presentation. Simply put, the atmosphere of San Diego is unparalleled anywhere else in the world. The amazing botanical gardens, dense forest environments, and the cornucopia of canyons and mesas create a maze of fascinating exhibits tucked into every nook and cranny. The collection is still remarkable and it feels like you could stumble upon another interesting species at any moment which is something few zoos are able to pull off nowadays. It's less organized than Omaha, but that's not necessarily a bad thing. While I just criticized many of the enclosures for larger megafauna, it's the small things where the zoo is at its best: the assortment of outdoor reptile habitats, the smaller but beautifully planted bird aviaries, hummingbird habitat, Australian exhibits, etc. Of course, there's also the huge walkthrough aviaries, multi-leveled primate enclosures, Africa Rocks, great ape exhibits, and the new buildings in the Wildlife Explorers Basecamp, so there are more than enough examples of wonderfully designed animal habitats here as well.
While Omaha has my vote for now, let me sleep on it and I'd maybe change my mind. I'm hoping to return to San Diego next year so hopefully then I can settle this internal conflict once and for all after a return visit.