Both trails are nice, and you do at your own pace, do you may be able to do each. Pagani has underwater hippo, meerkats, and gorillas. You can walk through quickly in 15 min. or spend a 1/2 hour doing it slowly. It is next to the Safari and LK show, so we usually do Safari first thing, then do the trail, then see LK show(usually with Tusker House brft in the middle!)
Maharah Jungle Trek in Asia has the tigers, bats, and Komodo dragons. Again it is near Kali Rapids, so if you are headed there, to Nemo, and Everest, you could walk through while over there.
There is also two trails that go up close to the Tree of Life, Discovery Island Trais, which have a few animal exhibits, but really cool to see Tree carvings up close, if you have time - in Discovery Island, can do them later in the day, as they are shaded.