It has a sense of fun and not taking itself too seriously. The characters in 89 Batman seem more like real people rather than random plot devices let loose in a city. Michael Keaton has a more upbeat and goofy presence compared to Bale's suave and cold presence, I enjoy the former a lot more than the latter. The cast itself and performances, even for minor characters, makes Gotham feel lived in, lively, dangerous. The cast in Nolan movies and their performances are all cold and sterile.
Nolan's Batman movies present themselves as being more grounded and real, if you tried to put the comics and the material in our world. While the Burton Batman movies are a mix of the comics and Burton crafting a world around those comics.
Nolan made perfectly reasonable but boring Batman movies. Burton made goofy as fuck and fun Batman movies.