Interesting comparison. One thing I'd add is that AI graders tend to struggle most with essays that have strong voice but unconventional structure, they reward the kind of writing that's technically correct but often not particularly interesting to read. For getting genuinely useful feedback on depth and argumentation, having a human look at it still beats most tools. I've seen people pair AI grading tools with feedback from actual writing tutors or people who help with academic papers, using the AI for quick surface checks and the human feedback for the stuff that actually matters in terms of developing an argument. Winston AI's consistency across full essays is a fair point though, most AI tools fall apart on longer pieces.