Scout (and the other children) love Miss Maudie for three reasons.
First, Miss Maudie was always welcoming to the children. Scout says that Miss Maudie allowed the children to have full reign over her property as long as they did not harm her azaleas. Here is a quote on this point.
Jem and I had always enjoyed the free run of Miss Maudie’s yard if we kept out of her azaleas, but our contact with her was not clearly defined.
Second, Miss Maudie cooked the best cakes in the neighborhood and she would call the children to partake. Any child would love this. Here is what Scout says:
She made the best cakes in the neighborhood. When she was admitted into our confidence, every time she baked she made a big cake and three little ones, and she would call across the street: “Jem Finch, Scout Finch, Charles Baker Harris, come here!” Our promptness was always rewarded."
Finally, Miss Maudie had a way with children. She could not only understand them, but she could also communicate an adult worldview to them. We should also mention that Scout spent a lot of time with Miss Maudie. Here is what Scout says:
I spent most of the remaining twilights that summer sitting with Miss Maudie Atkinson on her front porch.