Password Pad Lite uses XOR encryption, which has been obsolete for the better part of 100 years. It makes no sense to use XOR encryption, because one might assume that the data has actually been encrypted.
Password Pad “Pro” uses DES encryption, which was replaced approximately 10 years ago by the AES. Anyone wishing to see the history of DES and AES can look up the Wikipedia entry of the Advanced Encryption Standard. 256bit AES is far more secure than any implementation of the DES (including 3DES). It makes absolutely no sense to purchase software in 2011 that uses the obsolete DES for its encryption.
Your Mac already provides two free alternatives for securely storing text files. In the application “Keychain Access”, you can edit Secure Notes. By default, these will be encrypted with your login password, although you can specify another password if you prefer.
If you would like to include markup information (i.e., documents with fonts and size information), you can use the built-in application “Disk Utility” to create an encrypted partition and use the application TextEdit to create and edit documents on that partition. The 256-bit AES encrypted partitions from the free utility provide far stronger encryption strength than the obsolete 3DES could provide.
For managing passwords for website logins, several components are needed: a generator for creating unique passwords for each site, an encrypted database to store the account/password pairs, mechanisms to synchronize/backup the database, and browser plugins to automate the entry of passwords in login forms. The Password Pad products do a poor job at solving this problem; programs like 1password and lastpass do provide a complete solution.