While most security packages employ 128-bit encryption, Data Guardian goes a lot further with a super secure 448-bit level of protection.
The Blowfish protection system is enough to stop all but the most determined hackers from accessing your database or passwords. Data Guardian allows you to create multiple databases based on different themes e.g. an address book, customer database, journal, password manager, or even notepad. With 448-bit encryption employed on each of these however, they'll be pretty safe even if they're not stored locally.
The program prides itself on its customization support - i.e. you can create just about any kind of database you require with any category or color coding of your choice. The program also employs Keychain integration which basically autofills passwords. Although Firefox and IE also do this now, you're probably much safer using Data Guardian because of the encryption protection that surrounds your data. However, it would be better if Data Guardian provided secure integration with browsers too as it may be a bit inconvenient for some for keep going through Keychain.
It also offers a few other useful shortcuts such as one-click calling based on auto recognition of phone numbers, instant access to your email client via auto recognition of email addresses and generation of secure passwords. Although Data Guardian is a handy tool, it doesn't really match up to 1Password in terms of speed, ease of use and security.
A well designed a super secure database/productivity enhancement application, Data Guardian still gives you more than one less thing to worry about.