Urusei Yatsura OG > Manga.

The manga had a great set up and cast, but Rumiko focused way too much on similar comedy stories, without longer arcs (unlike her later manga) and rarely doing chapters in a different style, which makes things repetitive fairly quickly.

The anime has some problems of its own (mainly messing up some jokes from the manga), but it's just way more inventive than the manga was, after a while letting stories go in very different styles. It also works as a big time capsule of Japan's pop culture at the time filled to references to anything the animators liked.