I do not know this however I do think that whichever one you send your child to, it would need to be fairly close to home.
Say, I live in Morley, I would not take my children to a kindergarten in Fremantle, so I think it has to be fairly close.
The best kindergarten and preschool in Perth is whichever one best fulfils the needs of your child and your whole family. Personally, I prefer small nurturing places that affirm and encourage each child as a unique individual, and appreciate the Steiner and Montessori approaches to learning, so these would get my vote. There are several of each around Perth. Google them to learn more!