I recently tried migrating from Dropbox to OneDrive but I had to abort after three days of trouble. I was tempted by the 200 GB of free storage (for two years) and especially the extremely useful and unique feature called "Make available online-only". This feature would allow me to not only save space on my limited local drive, OneDrive would also - and this was the killer-feature I really wanted - give me local access to all files just as if they were actually on my local drive. Yay!
OneDrive leaves tiny "ghost files" locally that, when accessed, instantly downloads the real files seamlessly. This way only the files you use actually take up space. You can even see their file sizes, rename them, copy them or move ghost files without needing to download the real file. Great concept! I've been longing for this (and foreseeing it) for years.
I needed a desktop PC synced with a Surface Pro 2 (both on Windows 8.1) but it never worked. OneDrive (or rather the SkyDrive app) started crashing on Surface Pro 2 and it said 'All files up to date' even when 150 gigs were still not uploaded - and it didn't sync. I even reset it (skydrive.exe /reset) and ran thetroubleshooter (which asked me to move a symbolic link) and followed its suggestions. Nothing would fix it. The sync symbols appearing on folder/file icons stopped appearing even when the SkyDrive service host was still running.
I ended up deleting everything from OneDrive and move it all back to Dropbox (which quickly recognized almost all the files and synced everything without having to download everything all over again).
Lets you "keep" all files locally without them taking up space (like a virtual huge local drive).
Great Windows 8 touch app - at least as good as the Dropbox app.
Built into Windows 8 and is quite easy to access from any app/file requester.
Office files can be edited online - like google docs.
You can't 'Make file available online-only' before it's uploaded (why not just queue it for this?).
Videos shared (for viewing) stutter or won't always play (contrary to Dropbox).
When the Android OneDrive app uploads photos/videos it renames them and changes photos slightly. This makes it really hard to compare photos on your mobile or in Dropbox with the (similar) ones in OneDrive.
Symbolic links do not work (though they seem to), and the user has no way of knowing this.
Copies of conflicting files/ghost-files appear for no good reason (Dropbox would recognize they were identical).
Photos edited with Gallery on an Android Nexus device often end up broken in the OneDrive Camera roll (partly visible).