We finally found a workflow that works really well for text-based to do lists. Here it is:
We use BBEdit on our Mac Pro towers for our multiple text files, and open them in BBEdit as a “Project” so that all of the files appear in the sidebar for easy access (it’s not as cool as the tabs of Fraise, but BBEdit is much faster).
Dropbox does the syncing.
On our iPads and iPhones, we use Nebulous Notes to access the to do lists, again they are synced via Dropbox.