This is a really cool concept - like really cool - but I feel that it's not being executed very effectively. Firstly, the little icon that appears in the 'email' fields of sign-ups doesn't allow you to click on the icon, select the email you want to fill it with, and then actually fill the email field. It wants you to re-direct to the actual page, tab over, copy it, then paste it into the email field. Horrible? No. Easy? No. Not too much, but steps can certainly be reduced for better user integration/convenience.
Secondly, MANY websites will not accept these 'mozmail.com' email addresses into their databases. Many will tell you that they aren't valid addresses. I'm not sure if this is an error on the user-end xp, or if it's an actual attempt to halt Firefox from being able to re-route marketing traffic. Either way, this is something that the dev team should certainly look into. I think this has awesome potential, but there are a few tweaks that could make this a mastapeace. (misspelled intentionally).

Couldn't get email from archive.org.

No option to change the email address to forward emails to.
No option to get a generated alias address using the extension UI or with the right click.
Do not misinterpret me, the right click can only generate, not enter previously generated addresses.

It works, but you've got to be kidding me that using Amazon services maintains "privacy?"

Petness.pt does not accept. Sorry to say.

I think it has limited usage. Doesn't work w/ all servers eg: www.chess.com. It's useful for unidirectional application whereby server sends notifications outbound. It doesn't work w/ in reverse direction or bidirectional application.

would be better without the badge thing in the username / email field it ruins my site in a way it cuts of half the field, it needs to be placed somewhere else either above or to the side but not instead of. for context see page using the addon https://jnet.sytes.net/login.php

Great app with room for improvement. Unfortunately one cannot auto-fill any of the aliases and has to log in every time to retrieve them. Furthermore, there is no way to generate more than five aliases, and Firefox does not allow automatic completion of login information, at least for me using Bitwarden (using two-factor authentication under these circumstances just adds to the lack of user-unfriendlyness).

It's a good idea, but I need more than 5.

Only just started using this. Good idea, and worked great with the online retailer I used, mails were forwarded with little delay.

However the Relay icon that appears in the name field of log-on pages needs improvement (and ability to turn off). On some log-ins the icon overwrites other links, and on one it caused the box to contract so that it became unusable. If this happens to you, a current fix is to open the page you want in a private window (check Relay's settings to see that it is switched off for private windows first), but it would be good to be able to turn off this feature altogether.

Seems a good idea but it has integrated into site search boxes and removed filters. As an example my webmail client has a search box with filters for sender, recipient, subject etc. I now have no access to filters. Will now have to disable add-on each time it becomes intrusive.

Marcus by Goldman Sachs doesn't accept the e-mail address containing the relay sub-domain.

It doesn't work with twitter log in page :(

Usefull, but I would like to be able to fill the field from the extension button without having to go to another page (that would also avoid having to write a mail by hand when pasting is disabled)