I love Obsidian Sync as well but to be devil's advocate, it doesn't "just work" as a lot of people claim. It's still a bit rough around the edges. For example, it doesn't sync settings or starred files immediately. I've also noticed it dropping some text if I edit the same file on multiple devices simultaneously (or even in quick succession before sync is able to catch up). I'm sure these issues and more would exist with a 3rd party syncing solution but Obsidian sync still needs some work before it's perfect.
When I say simultaneously I mean typing something on a file on my laptop and then putting that away and making more change on my phone a few seconds later (sometimes the gap is even longer than that). Sync is pretty slow especially since it doesn't sync in the background.
