Joyce Carol Oates is one of my most favorite authors, I find her books are always engrossing and riveting reading .... though her subjects and characters are often disturbing & generate strong emotional responses (at least in me!). If you're looking for light easy reading then she's not the author for you IMO but if you like books that really absorb you & characters that live with you long after you've put the book back on the shelf then you won't be disappointed.
I think I've read about 14 of her books over the years and I can honestly say only one, "Mother, Missing" left me somewhat
dissatisfied .... in that I'd give it a slightly lower rating than her other books, maybe a 7/10 but the bar is set very high!
I would suggest starting with "We Were the Mulvaneys" which tells the story of how an assault on a high school girl impacts on her entire wider family .... as I said above the issues she takes on are not easy.
"The Gravedigger's Daughter" I would also strongly recommend, it's central characters are a German refugee family in the US in the 1930's .... again not easy!
I particularly like JCO because she creates very strong independent female characters, you won't find any swooning females in her books! She has also written in the short story format & if you'd like to begin with that you could try "The Female of the Species" & see if she appeals to you.
If you decide to take on any of her books I would be really interested in your opinion in due course .... either way I wish you happy reading whatever you choose JCO or another author.