Passwordless for a Microsoft work account with their authenticator app has been flawless for me.
If you're talking about broader passkeys, it's a very mixed experience so far.
In terms of storing and creating passkeys, Apple's keychain seems to have a pretty reliable implementation. I personally experienced a pretty horrible bug/glitch with Google and their Android implementation, where Google Password Manager would generate passkeys, give the public key over to the web site I was registering with and them seemingly discard the private key - making the passkey unusable. All this was being done while giving no indication anything was wrong. This was seemingly caused by having an old passphrase encryption configured on my Chrome data sync. The only 3rd party I've looked at is Bitwarden and its honestly unusable at the moment, they have passkey support implemented in the browser on desktop but not at all in their mobile app.
User experience on web sites and services supporting passkeys is also all over the place. Some treat them as a replacement for 2FA (ie. you still log in with a username and password and then supply a passkey). Some don't provide any tools to name your passkeys, so if you add multiple to an account you have no idea which key is which (should you need to delete one). On the sites that have implemented them as as intended (ie. as a replacement for passwords and 2FA tokens), then it does work pretty well.
It all probably needs at least another 12 months of people figuring stuff out.
