This add on is magnificent, I not only use it for my web passwords but also for my personal passwords including things like alarm and banking pins. I also made a group called bookmarks and I use it to store my most important bookmarks.
This add on does what they say it does and looks as secure as advertised. I disabled my router and was still able to get all my passwords from my local file both at work and at home. I can see the encryption every time I make a new save.
I cannot recommend it highly enough because I can now be at peace knowing I can travel anywhere and have my most important information at hand.
I used someone else's computer to check one of my accounts and he said his machine was behaving erratically. I used the screen keyboard to log on just in case there was a key logger installed. I'm so happy with this feature that I cannot describe it.
The only little bug I found was when I was changing a password the website would ask me to confirm my current password. The LastPass form filled in that field with the new password instead of the old. So in all cases I have to cut and paste to assure the correct information is in the correct fields. I'm sure this will be fixed soon, but in no way did it diminish my high opinion of this product.
I just posted the above on the Firefox website
I had to post here and tell you how extremely happy I am with the service.