I have moved from paper to PDA, then to a combination of both, back to PDA, and now, I use a "Month-at-a-Glance" calendar with PDA. I have to see the entire month for one aspect of my job, and there's no way the PDA can take care of that need. I don't have to carry the calendar every moment of the day, but it fits neatly in the book bag I carry, and I have it ready for the times I need it.
The info in the calendar is NOT in the PDA, so it's not a duplication of effort. I found that keeping that specific information in the PDA was not useful. I guess you could say the calendar is a tickler of sorts, but doesn't contain the kind of information one would normally keep in a tickler file.
I think we each have to find the way that works best for our own situation. Paper, PDA, both. What works best for you? I think that's the key.
Carolyn