Zap author here :) Logrus remains quite a bit more popular than zap. (Does anyone remember the epic tire fire when Sirupsen briefly changed the casing of his GitHub username?)

From my perspective, the problem with the KeyValuePairs API is that it’s inescapably slow and allocation-heavy. I’m glad that a logging API built into the standard library is usable in more performance-sensitive contexts. It’s easy enough to wrap it up in a KeyValuePairs-style API if you’d prefer that, and you’ll now have the ability to unwrap your logger and interop with other libraries that expect the standard slog interface.