My egghead video on Intro to ARIA might answer that question: https://egghead.io/lessons/html-5-intro-to-aria
Short answer: you should always start with semantic HTML because of what you get for free (keyboard focusability and semantics, style and behavior built-in). Sometimes, though, ARIA is necessary to expose accessibility information on custom elements. It doesn't add any behavior to the DOM, though, it only impacts assistive devices. It's one tool to have in your toolbox, knowing that you should reach for native elements first so you aren't having to recreate what browsers give you.