This is an absolute must for me. I have like 50+ internet accounts, all with secure passwords. All I have to do is remember one master password. There are other password tools and generators that are perhaps more popular, but NONE so powerful as this one.
The level of control over password generation is unparalleled, bar none! And yet, it's so easy to use. You can create groups, and within those groups, you can have accounts -- each with specific parameters regarding that particular password. You can specify pretty much every aspect of the password: the length, the character set, whether to auto-populate, any modifiers to hash in, l33t level, l33t usage before and/or after password generation, any prefixes and/or suffixes, username, and hash method. I mean, what more could ask? If you don't want that level of control over each password, you can specify global settings and have at it.
Once the password is generated, it will show you the relative strength of the generated password (and this, my friends, is key). You can also specify auto-complete fields. Other password extensions don't do any of that.
TIPS I have found helpful:
1. hold ALT and press the ` key (left of the number 1) -- this activates the CoolKey and fills in all password fields
2. changing the character set order, can change the password
3. you can export your settings -- in case your computer dies, or you have more than one computer, or more than one OS
4. because you can create accounts, I use it for non-net accounts
This is really the most sophisticated password extension available. There are many features I haven't even touched. This extension is for net novices AND net know-it-alls alike.