Not much, really. She is a very good writer and she does have a good mind, that is, well-furnished, but like the majority of the members of the chattering class she uses her talents to promote a world-view that is mean and terrifying in its indifference to the individual outside of the class or caste into which they have been placed by the chatterers.
This world-view doesn't apply to the chattering classes. In their grand schemes for socialism/communism's triumph, they see themselves apart, above the rest of us, administrators of the collective to which we are assigned.
Some may assume this attitude because it promises financial and social rewards, but a lot of them seem to have had their brains dipped in an acid bath of Marx and Freud ("that Viennese quack," as Nabokov called him;} to have an original thought, independent of these two alien streams in 20th century Western thought, is almost impossible. True thought requires freedom from cant and hypocrisy, the rotting foundations of Leftist orthodoxy.
Miss Brown's early and impassioned dedication to "buzz" as a means of social and professional advancement attracted the socially and intellectually insecure to whom an Oxford degree and a plummy accent were the sine qua non of "classy." This, and the mindless acceptance of Marx and Freud as the interpreters of reality placed Miss Brown in the curious position of fawning over and being fawned over by a class deemed worthy of extinction by Marx and his followers.
It's regrettable that Miss Brown used her considerable talents for such shoddy ends. Now, she is dedicating her time and skill to writing a biography of a young woman of privelege whose decisions made her personal and public life resemble a multiple car-wreck. A pointless waste of time on a pointless waste of space.
Still, it makes me uneasy to read personal attacks on public figures on FR.
Some of the attacks on her do seem petty and possibly malicious. But I'm not sure who you're referring to when you say her work is highly respected. Many in the profession laugh at her.
Ideology aside, from what I've seen of her work, it's short on substance. Her magazine and her talk show have both failed. How many commercial failures must she have before it's conceded that she just can't deliver?