as others have said, it's super easy to learn the korean alphabet. I had to do it for an intro writing systems class. but the grammar is hyper agglutinative . That means it's a ton of suffixes and prefixes to make your words.

I don't know a lot about mandarin (which is what I assume you mean with chinese), except that the grammar isn't too intense. The characters and tones might be trickier, but I've heard that you can get away with not knowing everything, and you can piece things together sometimes.

at the end of the day, which language you study should depend on which is more fun and interesting for you. my interest in Mandarin is mostly utilitarian, since I imagine it will become much more of a powerful langauge compared to Korean. That being said, there is obviously a lot of really interesting media coming out of Korea, so that could be more fun to help you practice.