There's no such thing as "better" but it is more accurately..."what is better for you?" or "what is better for this project?"
I use MySQL because it's simple and most of my database projects are fine on it. Most "nerds" that I know strongly prefer MariaDB for performance. I haven't personally tried it or felt the need to stray from MySQL. Do you have any experience in one or the other? What's making you look more at Maria?