I was very impressed!
It's massive - the animals have vast areas in which to roam, so much, that it barely feels like a zoo. There is a little train and a bus that can take you round if you don't feel like walking. (it's not a Safari Park)
I loved the Mara - (photos at the bottom here) they run free around the entire zoo. At first I had no idea what they were, they bother no one and are so cute!
See the pictures on Flickr