they are not competing

they handle two different cases

anyhow is for type erased errors, which is mainly used for the kind of errors you mainly propagate upward without handling them in any fine grained way. It's mainly used in applications (instead of libraries). For example in a web server anyhow errors will likely yield Internal Serer errors.

thiserror provides a derive (codegen) to easily create your own error. It's much more often used by libraries, but if an application doesn't want to handle this errors they will likely be converted into anyhow errors. A very common use case is to apply it on an enum which represent "one of many errors" e.g. as a dump example `enum Error { BadArgument(...), ConstraintViolation(...), ... }` and it's no absurd in some cases to have a mixture e.g. an enum variant `Unexpected(anyhow::Error)` which represents various very unpexted errors which likely could be bugs and you might have considered panicing there but decided to propagate them instead to avoid panic related problems

Download counts don't mean very much here as I'm fairly sure both crates are common transitive dependencies. Or in other words, millions of programmers aren't individually choosing Anyhow or Thiserror on a monthly basis -- they're just dependencies of other rust crates or apps.

And agreeing with the other reply, nobody jumps up and down with joy when choosing an error handling crate. You pick the right poison for the job and try not to shed a tear for code beauty as you add in error handling.