So far so good.

Helps tremendously. I have already observed it working on a contest site that I had to enter an email. Only complaint is when in settings -Show relay icon in email fields on websites is turned off, it turns back on when browser is reopened. Sometimes the icon has prevented me from entering sites that already have a user name/password saved to it.

Relay is great. however Apple iCloud doesn't seem to accept forwarded emails from the relay. so atm I would advise others not to use it with their Apple iCloud Accounts. (Spam filter?) emails aren't even showing up in junk so apple is straight up denying these emails in from the relay.

Just one little problem. I can't login to my Wolfram account (account.wolfram.com) with the extension enabled. Weird.

Great Idea

while there is option to create new alias, while filling a form, it will be good to have an option to fill existing alias. May be someone want to use 1 alias at multiple site.

This extension is absolutely great! Only one page broke due to this extension: https://sacola.magazineluiza.com.br/#/cliente/login/?next=/acompanhamento/&origin=magazineluiza

When trying to login, the email input field on the left stays on top of the reCaptcha prompt, which makes it impossible to read what I should click on.

Good work Mozilla!