Welcome to the site - :approve:
As the PIM functions are one of the most widely used on a PDA you will find that there are large number of users of both on this site and every now and then they post their thoughts about one or the other (or both)
Do a search on this site for the following:
- Pocket Informant
- PocketInformant
- PI
- Agenda Fusion
- AgendaFusion
- AF
And you will get enough reading to keep you happy until Christmas -
BTW - they are both excellent and most of the time it comes down to personal choice (or even which one you try first!).