Ultimately, the best way to decide whether you prefer movies or series is to try watching a variety of both and see what you enjoy more.
Personally, I enjoy both movies and series, but I tend to prefer series. I like the fact that I can get invested in the characters and the world over a longer period of time. I also like that there is more room for character development and world-building in series.
However, I also understand why some people prefer movies. Movies are typically more visually stunning and have more satisfying endings. They are also easier to watch in one sitting, which can be a plus if you don't have a lot of time to spare.
So, which is better? Movies or series? It really depends on your personal preferences. If you are looking for a shorter, more self-contained experience, then movies are a good choice. If you are looking for a longer, more character-driven experience, then series are a good choice.