I voted Zurich 3 Antwerp 0, but will change that to 2-1.
Antwerp strengths in terms of ungulates are the buildings, not so much animal welfare. The Moorish temple with Okapi & Red duiker is a lovely building, but the enclosures are mostly smallish, but Antwerp's record with this species impressive. Similarly the Egyptian temple with Giraffe, Zebra and Elephants is one of the most beautiful zoo buildings in Europe, but especially for the Elephants it does not suffice at all... The Buffalo aviary is a wonderful enclosure, but mainly because of the birds, for the Buffalo it is fairly average, but still clearly better than in neighboring zoos with this species. As a note, the nocturnal house will close soon (unfortunately), I am not sure what will happen with the Balabac kanchil. The Tahr and Takin are also due to leave / have left already and will make place for Barbary sheep (pure subspecies), but the paperwork to get these from Spain is quite demanding...
Ungulates are still not Zurich's strength, but they have what is I think the most impressive Elephant complex on the continent. There is broad agreement that the indoor housing is easily the best in Europe, but outdoors is also good. It might not be very spacious, but is filled with enrichment and feeding stations, so it makes for very active elephants. The whole complex is so versatile that they can keep 3 separate Elephant groups there in perfectly fine circumstances, as they have 2 full grown bulls + 2 separated matriarchal lines. They would be happy to send one of the female groups away, but they haven't found a zoo that could give the same level of care.... By having multiple off-show and on-show indoor and outdoor enclosures all groups are rotated throughout the day between the different enclosures, which keeps the Elephants as active as possible. Such excellence alone would be good enough for me to give Zurich my points and the other Hoofstock also cannot complain, though most of their paddocks are somewhat more boring. Noteworthy for people who consider future developments, in 2020 the Lewa savanna will open, which will be a huge paddock for White rhino, Reticulated giraffe and Grevy zebra mixed with several antelope species.
In terms of conservation Zurich contributes financially to Elephant protection in Kraeng Krachan NP in Thailand as well as to the Lewa conservancy in Kenya which has high densities of white + black rhino, as well as other endangered species like Grevy zebra. Total contributions to conservation of Zurich are about 1.2 million USD per year, but I am not sure how much money goes to these two projects.