Thanks for the additional info; I was not aware that DTPO had been updated with the better syncing capability. This is not surprising, though - the DTPO developers seem to be first-rate.
I should have been more precise with my thinking on data access on mobile devices. I really like to have certain data available on the desktop as well as on mobile devices (phone, iPad) - certain receipts, current articles to read, technical information, etc. I agree that you would not really want information such as old tax returns stored on mobile devices.
It's really a matter of data organization. What type of data to store in DTPO and what to store in Dropbox, synced to phone and iPad? Or what to store in local, but accessible storage such as Transporter or Pogoplug? I don't really need to be sitting at my Mac to work (read, research on internet) and add stuff to my database. I can do a lot of this from a laptop or iPad.
James Floyd Kelly discusses some of these issues in his excellent book, "The Ultimate iPad".
So many decisions, so little time ...