Best folder/file syncing solution for my needs?

Sounds like maybe BitTorrent Sync might be what you want. You're not looking for a cloud-based solution (get to files from anywhere), you're more looking for keeping a particular set of files on both machines.

Obviously something like Dropbox could be used, but with that your "hero" copy of the files become the ones in the cloud, which may not be what you want.

 

i use good old rsync to external drive then back... works wonders.

 

So you just ignored my post, then.

 

Sugarsync. It works similar to Dropbox only you can sync the folders where they are rather then moving them all into the dropbox folder. It also keeps everything you delete (in a separate section of your storage) until you tell it to remove those files from your account, and does versioning.

ETA:
As far as downloading for a weekly backup - there's no need to ever do this unless you've disconnected a folder from your backup/sync set and forced it to live only in the cloud. Otherwise, everything that's in the cloud should be on your machines (depending on how you've set up the sync of course).

 

I have a similar setup. I have two Mac Minis in far apart locations and an Air on the go in between. I use BitTorrent Sync to have identical copies of my Documents, Downloads and my iPhone's picture in all my Macs.

My Documents and Downloads folders are well organized with many sub folders. BitTorrent Sync preserves all the folder structures and sync only the files changed.

BitTorrent Sync has two major advantages: 1) You have your own private cloud, so none of your files reside in someone's 3rd party cloud server. 2) When the machines share the same network, syncing is done locally (faster) and syncing over the internet is used only when the machines don't share the same network.

For up to 5 folders (each folder can have unlimited sub folders) BitTorrent Sync is free. For unlimited folders or group sharing, it is $40 per year.

For my needs, the free version is more than adequate.

 

Dropbox syncs in near real-time (within the limits of the data connections to the syncing devices anyway). As soon as you change a file on one device Dropbox syncs to all others when they become available. "Hero files" is a bit of an outdated concept then.

Failing that, BitTorrent Sync. Or Copy, Or Box etc etc, only iCloud has a files-not-folders silly limitation (if it does, I've not tried it)...