The zoo is huge and a lot of walking so be prepared to walk. There are a lot of animals so that's a positive.
however I was a little disappointed with there pricing as its pretty expensive plus they also charge $10 for the parking on top of the $28 entrance fees. The food is very expensive so are the drinks and you are better off taking your own food and drinks and that's what we did as we were a group of 20+.
Apart from that it is amazing to walk all the animals from around the globe. The zoo is divided in continents/regions. The highlight for me were the White lions and Pandas.
On a separate note if you a group of 20+ you get the entrance for $25 and don't have to wait in line just go to service desk pay up and there is a separate entrance for big groups which is faster to get in.