Simple and works Rated 4 out of 5 stars
I've been using this plugin since 2007 - and it works perfectly.
I normally use the enter masterpassword +F2 function as the password visually gets 2 char longer
For a full review see http://edgecrafting.blogspot.com/2007/08/pwdhash-one-password-to-rule-them-all.html
Tip for Beta users;
bypass the security check by adding the preference extensions.checkUpdateSecurity and setting it to false (though not recommended for casual users).
type about:config in the address bar and press Enter
1. Right-click -> New -> Boolean
2. Name: extensions.checkUpdateSecurity
3. Value: false '
Restart browser and install plugin