It's true, Google Drive and Dropbox are free to use and easily accessible, but they also come with some notable privacy concerns. The privacy policies of these two services are lacking, and the features you need in order to control who can see your files and collaborate on them are equally weak. If security is a priority (and it should be!), we'd recommend sticking to one of the cloud storage providers mentioned in this guide, and checking out our guide to cloud storage safety.