Google Drive is all about cloud storage and letting you access your files no matter where you are or what device you are using. Like Dropbox, you can specify a directory on your computer that is then synched to your Drive account. You get 5GB of space for free; you can move up to 25GB for $30 a year.
Google has made collaboration easy and allows you to share a link to a file or to a folder containing many files. Google Docs is available to Drive users, so you can use the Google Docs editing tools to work with your files.