What is the advantage of this over the parser used by xsv? From the documentation, the only difference I can see is that xsv handles weird CSV better than this crate-- which in some situations is very important! So presumably this one must be faster? If so, how much faster? Or is there some other advantage to this?

There is a section here with a table describing the kind of boost you might observe vs. rust-csv used by xsv: https://docs.rs/simd-csv/latest/simd_csv/#regarding-performa...

It would be useful to see how it compares to this .NET parser: https://github.com/nietras/Sep