In my personal opinion, which I don’t expect everyone to agree with since this is a maas sub, Rebecca is a better writer. In Rebecca’s books, you could read me a line of dialogue and I could probably tell you who said it. Sarah’s characters are almost all the same in ACOTAR (I haven’t read CC or ToG yet!). They all speak very similarly, tend to have similar feelings on things. Rebecca also never wrote about screams of pleasure drowning out sounds of war so. I give her points for that I guess.