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Despite all problems with the App in recent times («no internet connection» bug) I still like Dropbox a lot. Almost seamless finder integration, much faster and reliable than iCloud, relatively fine-grained control. I'm not sure LAN-Sync is back, but that is due to Apple (as is the stupid new location in the library, basically Cupertino kneecapping the competition. Being able to check a file on the go, have backup of the current project files etc... I still haven't quite found a replacement yet, although there is some competition. I liked «paper», but most of the tangential stuff DB offers is not for me, really. Maestral is a very nice piece of software, but I always preferred the original app, despite it being wrapped in Electron... it just works more seamlessly with finders etc.
 
Dropbox's standard client does try to shoehorn too many functions into one bucket. I don't find it to be a problem on my M1 Air, but it can be a burden on Intel machines. Having said that, it has been rock solid for many years in my experience, both using the business and personal editions.

If you're interested in self-hosted approaches, you can investigate solutions like OwnCloud and NextCloud, to start.
 
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