Simon Willison's objection to Jev is that the output is a single float.

His September 21 post calls it good for classification, spam detection, labeling, prioritization and ranking, then names the problem: "put in all the text you want, the only thing you're going to get back is a floating point number," with no reasoning trace to audit. He demonstrates by asking Jev to rate Bay Area cities on a "good city" metric, getting Cupertino at the top and East Palo Alto at the bottom, and warns explicitly against employment screening. A float has no audit trail, and hidden bias in a float is undetectable by construction. (simonwillison.net)