It doesn't have a great cross platform support (no Linux client, and there are many complaints for the Windows client).

Personally, I dislike that you cannot restore an older version of a file on laptop/phone, and must instead use their web app, for which you need to disable ADP, which defeats its purpose.

Mounting Dropbox on Linux machines is really easy. Google Drive has terrible support for binary files and namespaces.

For business purposes I didn't want to use iCloud. But it seems like it's iCloud & Dropbox then.