While the show's ending in terms of the original series was abrupt and disappointing for fans, "Serenity" provided a fitting conclusion for the main storyline. It's important to note that the movie wasn't necessarily intended as a direct continuation, but rather as a standalone adventure that expanded upon the universe established in the show.
So, technically, "Firefly" ended with the cancellation, leaving many questions unanswered. However, "Serenity" provided a more definitive ending for the core story, offering fans a sense of closure.