Setting up syncing - best way?

There is no best way. Here are some details…

Works with DTTG Pros Cons
Bonjour Yes • Fast, private, generally reliable
• Direct machine-to-machine syncing with no intermediary
• Requires devices to be on and our app(s) to be running
• Only works on LANs permitting Bonjour or non-standard port traffic. Does not work over VPNs.
• Firewalls must allow exceptions for DEVONthink traffic
Local Sync Store No • Very fast and private
• Can be located on an external drive or a shared resource, like an NAS
• Doesn’t require other Macs to be on. They can sync when they’re on and running DEVONthink.
Only for Mac-to-Mac syncing
• Requires access to the volume or machine where the sync store is locaterd.
Dropbox Yes • Generally reliable
• Direct sync with Dropbox servers
• Any cloud service can have slow/unresponsive servers, limit maximum connections, and throttle bandwidth.
• Questions of privacy, but can be offset using an encryption key.
iCloud Yes • Generally reliable
• Easiest to set up
• This is a two-stage sync: syncing locally first then iCloud does its own syncing.
• iCloud can stall (which is beyond our control or detection).
See Dropbox Cons.
WebDAV Yes • No inherent advantage, but may make other cloud services available to syncing
• May be hosted locally, even with some NAS products.
• The reliability of a local setup may vary.
• Local servers / NAS devices may require more technical expertise to set up.
• If using a public cloud service, see Dropbox Cons.