Far from perfect. It is not very consistent, sometimes it fails to capture the username, sometimes the password in quite a few websites: about 1 in 10 websites has some kind of problem, my bank (piraeusbank.gr), my Camscanner login (v4.camscanner .com) and politico.eu login page, among others. In the case of politico.eu, the login would completely fail: I couldn't login at all unless I uninstalled the add-on. I have reported these pages, but nothing happened.

I installed Proton Pass because I wasn't happy with Firefox's default password manager either, but since it isn't perfect, I don't see what the advantage is over the (also not perfect) Firefox default password manager: all that changes is which websites don't work. I suspect my problems are Kubuntu Firefox-specific, but the result doesn't change. I'll return to Firefox default password manager for now

I used to use Vaultwarden (a fork of Bitwarden's open source, self-hosted password manager - I do recommend it!) but decided to use Proton's solution since I have moved over to their ecosystem for everything else. I've used LastPass years ago and the comparison to Proton Pass isn't even fair; Proton really has nailed the UI, experience, and details of Pass. Unless LastPass has really changed things, their system is a combination of their old interface and new interface with some features seemingly half-complete. Plus they've lost my trust. Proton on the other hand seems to have a much better architecture for the security of accounts as well as extra layers of safe-guards that can be added if desired.

I highly recommend Proton Pass to everyone!

unable to understand how it works, sometimes appears when making a new sign in sometimes don't

Simple and sleek. How every app should be