Onedrive is actually mediocre.
Just recently I was considering a file sync service because I intend to code in two different locations, and once again, after trying a multitude of solutions, I was driven back to Dropbox.
It's truly amazing how Dropbox remains #1 simply because it does all the things one expects.
You know what Onedrive DOESN'T DO? The #1 feature expected from a file sync service, of course - incremental file backups.
So when I change one character in my Visual Studio project, it uploads 47megs! Dropbox uploads probably around <300k in the same situation.