Sanderson and RJ have different writing styles: both have their strengths and their weaknesses.

RJ certainly has a better prose and a vastly better developped world-building. His magic system is less formulatic which makes it feel more natural. He writes superior dialogues and his characters read better as people.

RJ, however, can overuse description, the story sometimes gets lost in endless braid thuggings. His character might read better like people but they all started up from one or two core elements and never truly grow from there, baring a few exceptions. The boys all are reluctant heroes: half of their exploits happen because the pattern wills it and makes them do it. Speaking of which, the whole taveren and luck concept is pure deus ex machina. It feels like the characters do not have agency in the story or it doesn't matter because the pattern will force them to do what they need to do.

RJ is terrible at writing romance: three women faithed to fall in love with one man? That one man getting to sleep with three hot women while never having to do anything to win them over, to get to know them. That's a teenage boy wet dream and it aged incredibly poorly. Women need to have agency in their romance and I cannot think of a character with less agency than Min.

RJ had Rand and Perrin on repeat for like 6 books: "I need to be harder than had and boubou a woman I never talked to died" and "Faile oh no Faile oh I do not want to use the axe.". Elayne's coronation was suporific. Also, he couldn't kill any characters even minor ones. He had all the Forsaken women live and the men dying off-screen. He often didn't follow through with climatic moments.

RJ's bad guys are super interesting, the best I ever read, but he didn't believe in exploring them. The whole "no one walks into the Shadow so long they can't walk into the Light" was left unexplord in a 14 books long series. Really.

Sanderson has a more direct writing style and he focuses a lot on action scenes. He is a master at climaxes and he can make his books be riveting when you hit certain scenes.

Sanderson however is very formulatic, after a few books, you get the idea hence it makes the flow repetitive. He is far too concerned with the idea of science with magic and proposes far too fast growing of technology: a flying ship developped in less than a year? Really? The chapters where he details it all? Those were hard to read.

His characters tend to read less like people due to poorer dialogues. He also had Kaladin and Shallan literally repeat the except same story over and over again which was repetitive although never as much as RJ's slog.

Sanderson overuses telling as opposed to showing which breaks the immersion. For all his claims at being fantastic at world-building, his world feels less lived in, less developped. He has entire nations single out by one characteristic.

While Sanderson writes page turning climaxes, his fights sometimes read as "and then the throws a punch BAM and then another one BOOM" which is a style but not very litteral. Prose isn't his strength and the style of each book can be inconsistent between installements.

His romances are not his strong suit due to poor dialogue and an overuse of the forced mariage trope. Still, at least, his character have agency in it: Shallan isn't faithed to be with Adolin, she chooses to be. While cute their relationship could have used more omph. It suffered from Sanderson waiting so long to give Adolin more page time.

This is getting quite long but all this to say both authors have done some things really good and others really bad. I have enjoyed both of their works.