The indoor exhibit for Columbus is bigger, and has a few fake trees with hidden hay in them. They get the edge on attractiveness for having it look at least a little natural for their indoor exhibit. Plus you get to see a black rhino. As for Cincy's indoor exhibit, they do not use concrete, and you could probably touch the elephants if you wanted to. At Columbus you're behind glass.
As for the outdoor exhibit, Cincinnati gets the edge for attractiveness because they do not use bars and large wires as fencing, they use fake rock, moats, and few feet tall chain link fences hidden in the trees. The down side is that it is only .6 acres while Columbus's is 1.5. For Columbus they use large vertical bars and horizontal wire, ruining the view. The only open view is by the pool, which they were not at on my visit (they were inside). Because of the size I like Columbus's more but for experience Cincy wins.
You've compared the two zoos in regards to a couple of photos and in my opinion in 9 out of 10 exhibits the quality is higher in Columbus. Whether it is elephants, giraffes, practically any type of hoofstock, all the bear species, manatees, koalas, kangaroos, tigers, lions, Komodo dragons, otters, bonobos, bats, etc, Columbus has superior exhibits. There are a few exceptions to this rule (for example gorillas and orangutans have slightly more impressive enclosures in Cincinnati although neither zoo shines in that department) but overall Columbus is simply fantastic while Cincinnati has a great animal collection but mainly average to mediocre exhibits. Of course this is all purely subjective and my own opinion but it is a rare zoo nerd indeed that would disagree.
