Rated 5 out of 5 stars

The addon is great. The enhancement of existing password manager is great too. By the way, is this addon secure or will it transfer any data to your server? I tried google but found no site mentioning nor reviewing your addon. This is the only part that I am worried. Thanks

This review is for a previous version of the add-on (2.9). 

it is secure!

Yes it is secure - it doesn't do any communication with the "outside world". the only way you get passwords over back and forth is via the built in "Sync" mechanism of Firefox, and AFAIK it uses Mozilla servers and encrypts the information.

BTW, Addons published AMO must give a privacy statement if they transmit any user data, they are very strict about this. QuickPasswords simply works with the passwords stored on your local machine and inserts them to pages / clipboard.

One thing QuickPasswords doesn't do is display passwords on the screen (as I find this counterproductive), I leave that to other addons. For more control over your passwords, I recommend also installing "Saved Password Editor".