One thing that comes to my mind is distance.
My thinking says that playschool should be near to the home. As it does not make sense for small kids to spend time in traveling and its good to be accessible as for small kids may need you any time.

One think that I looked for is that there is a good mix of kids in the school. I do not want to send my son to a school where there are kids from very rich family. I want my son to grow up like a middle class child so that he is ready to face the life when he grows up.