Which sites/platforms use recaptcha, and which have the worst success rate?

Which sites/platforms use recaptcha, and which have the worst success rate?

Can anyone that has engines without recaptcha and with those with bad success rate send me their engine selection maybe?

Thank you very much!

anyone?

Recaptcha is owned by Google and they allow anyone to install it on their website to help fight web spam. So there's no specific web engine/platform that only uses recaptcha as a result..