I am very impressed with the Phoenix Herpetological Society! We took a group of school children there last Thursday and we were all very pleased with our experience! Our tour guide (I'm sorry I forgot her name) was very knowledgeable about all the animals. I would definitely suggest taking children and adults!
The tour is mostly outside and practically in the middle of the desert so make sure you plan accordingly! Bring water, closed toe shoes, and slather on the sunscreen!
This tour is by appointment only because the land used to be someone's house and is by other houses. My only complaint is that it took a month or so to officially schedule an appointment but it is well worth the wait!