It does function and allows cross platform interoperability with mobile and other PCs. That said, the Firefox extension seems to have been largely left to rot. The extension logs out constantly and requires re-entering the master password a dozen times a day. Firefox Lastpass is also missing features available in other browsers. There also seem to be more and more logins that Lastpass fails to autofill for all the time and has a bad tendency to want to create redundant site entries.

On the plus side, Lastpass under Firefox is more responsive than the Edge extension

Works quite well

On Windows 10 v1803 with FireFox 60/61 Login into LastPass is impossible. Even older versions of LP as suggested in some workarounds do not work.

Did a clean reinstall of FireFox, afterwards installed LP as only plugin. Thus it's definitely not a corrupted profile.

LP works with Opera and Edge.

Other plugins work with FireFox.

Conclusion: LP for FireFox on Windows isn't maintained any more.

I like the iOS app much more than I like the Firefox Add-on. Works about 90% of the time here

Took forever to find the "plug-in" for Firefox, which isn't called a "plug-in" but rather an "extension" or an "add-on".

Doesn't always work on firefox but works on Chrome and Edge.

It really sucks on Firefox.

Works on Firefox, Chrome, IE and Android. Perfect password generator & secure online server

Что с расширением стало? Почему его Firefox выключил?

This is an amazing password manager. It is secure, easy to use, and, once you are in, you can add it to any device, and your log ins are there.

Premium version works great across 2 laptops and android phone. Looking at family version.

since almost a whole year (Nov 2017 - July 2018), they did not restore the copy username / copy password functionality for Firefox on Linux. Quite a shame to decrease the functionality of your product with an update and then being unable to restore it...
Otherwise great product in general.

The extension is really good on Chrome, but on Firefox you can't easily copy the password from menu. The extension won't auto-fill many websites, so you have to open the menu, find the site, go to edit, show password, copy and then paste into the form. Really annoying!
Please, make it work the same way and with the same menus Chrome has.