Bad interpretations of law. Concerns about her decision making in her personal life. Stuff like that.
The abortion position, ACA, and such are (i believe) non issues at the end of the day.
Tl;dr: I don’t think there’s anything you would characterize as “grossly negative” from what I’ve seen so far. I can understand why others might feel differently.
She is in the minority quite a bit in her circuit, which could be troubling, depending on the relative reasonableness of the circuit, which I haven’t looked into. She has a limited record based on lack of judicial experience, but apparently has a pretty strong history of academic writing (Again, haven’t gotten to that, yet). That can be both qualifying and insightful.
Her 1A-6A jurisprudence, which I have looked into a bit, seems fine. She seems about like Scalia: she’s willing to take a strong view of a defendant’s rights but was less favorable to a prisoner’s rights. She’s strong on 1A, which is a net zero because there are already 5 very strong 1A justices, and she is strong on 2A which, again, is mostly a push.
The only real issue remaining, IMO, is how strongly she will respect established precedent. I think that’s more important than most people realize with Dems threatening to pack the court. Flush that norm and we really will have a constitution that rewrites itself every time one party gains full control of the government and adds 2 seats to the court.
So, that’s why I would have some concerns about the effect of overturning Roe. There’s evidence that she’d only be the second vote to do that, if she were so inclined (of which there is almost no evidence). So, it’s not a huge concern. It would be more problematic if Hawley insists that she pledge to overturn it and she does, because I don’t think many people are going to be placated by the fact that Thomas wrote a dissent calling for it to be reversed this term and 0 justices joined him.
On balance, she seems fine so far. I don’t have anything other than procedural concerns, but that’s really unrelated to her qualification. If I found something that makes me think she’ll try to gut existing precedent, I’d change my mind. But it’s hard to find that from a lower court judge whose decisions are subject to review.
Re: ACA, I think the individual mandate will get severed and eliminated, and the bulk of the law will survive. I think this outcome will likely get 6-8 votes. Roberts will probably write the opinion and people on the right will lose their minds.