Thanks, Section8.
At this point, I've gone back from the Dropbox sync to the wifi sync. I've had a couple more issues:
1) Recently, I opened my iphone app after what I thought had been a successful sync, to discover that all of my tasks were gone--the iphone had absolutely nothing in it (not even topics, contexts, etc). A later successful sync brought it back, but there was no way for me to tell while it was happening that it had wiped everything, and it wasn't very convenient to discover this while out and about.
2) This morning, I tried several times to sync, and every time, it would get as far as uploading my thoughts from the phone to the desktop app, then hang; none of the rest of the sync process would complete. Did this a bunch of times, and restarted the app, to no avail.
If you get more bugs worked out of this, please do let me know, as I think it'd be useful. But at this point, it's not ready for the public, IMO.