Dropbox. I've used it for a decade, but now it's slow, bloated, and takes over CPU and memory like there isn't a single other program I need to run... and I was paying $20 for the privilege. But a few weeks ago I switched to Syncthing[0], and it's the best software transition I've ever made. Opposite of everything Dropbox is now: fast, simple, and I don't even notice it running in the background. Seamless setup, and…
The problem with Syncthing for me is that there is no bi-directional syncing on Android if your files are stored on an SD card. You need to resort to rooting your phone or messing with a bunch of hacks to overcome this issue. Otherwise, its great.
I'm using a Moto g5 plus phone with android 8.