Not to get all semantical about this, but then it’s unsafe. Users don’t care about the plumbing. They care about their data.
There never is a guarantee that all the instances are up to date, for if you have several instances it is always possible that both instances are changed at the same time. Therefore the most you can aspire to (and the thing developers of sync technologies should aspire to – it is very difficult!) is that such changes do not result in data loss or verification errors.
Actually, that’s precisely the reason why if you have more than two instances using a sync store is more safe than sequences of direct syncing: there is no risk of data loss if you accidentally deviate from the established sequence.
Original poster here. I’ve deleted and re-created two of my three DevonThink databases and Dropbox sync is working really well. I’ve tested on as many computers that I could gain access to for this test (four total) and have had no issues whatsoever. FYI, only two of these machines are “mine”. These two databases total about 2.5GB in size.
However, I have given up on creating a large email archive database. I don’t know if there are problems with the original email messages, attachments, problems importing into DevonThink, syncing a much larger file both in terms of individual items (about 16,000 I think) or size (whatever size I posted before, not sure any longer). This sync didn’t complete in over 40 hours with Dropbox nor could I get it to successfully complete using a local USB sync store. Copying large files or even the DevonThink database itself that wouldn’t sync properly to Dropbox would complete in a fraction of that time, approximately 20 or 30 minutes.
Overall, I’d say I’ve adjusted my expectations and DevonThink is meeting them nicely.
A couple of things. Careful when you’re sync’g as you’ll get the dreaded sync conflict and you don’t want that trust me.
Secondly, I believe the speed of the Dropbox sync has more to do with Dropbox and the nature of the system sync’g to it.
The speed is fine as just let it do its thing in background and go on and do your business. Don’t let it stop your workflow.
The key is to stay efficient and effective. DEVONthink Pro Office is stable now on sync.