For simple storage, Amazon Cloud Drive is OK. Not great, but OK.
Amazon Cloud Drive comes with 5GBs of free storage. For more storage, Amazon charges approximately 50 cents per gigabyte per year. So, for example, 20GB will cost you $10 annually and a terabyte, 1,000GBs, will cost you $500 a year.
You can access this storage from either a Web interface or using apps for Android, iOS, Mac OS or Windows. There's also a special application built into Gen 5 Kindle Fire devices and later.
What Amazon Cloud Drive doesn't have is much more than basic file synchronization between the cloud and desktop operating systems. I like Amazon Cloud Drive, but it's best for simple personal file storage rather than business storage. For that, what you want is Amazon Simple Storage Service (S3) and that's an entirely different level of cloud storage.
Box, no relative to Dropbox, is far more than just a simple cloud storage service. It's also a business-collaboration and work-flow service. In particular, its native Windows Phone and Windows 8.x apps Office integration lets you open, save, and share files from the cloud without having to leave the Office programs. Windows and Office users might find Box attractive... except Microsoft has its own outstanding small-scale cloud storage service: OneDrive.
Box starts at its Personal tier with 10GBs of storage and a 250MB file size limit. You can move this up to 100GBs of overall storage for $5 per month. Where Box really starts to shine for SMBs is at the Starter Level. Here you get 100GBs of storage for one to ten users at $5 per user per month. Besides simple storage you can lock files, set them to automatically expire, assign permissions to them, and keep up to 25 previous versions stored. Above that, the Business tier, for $15 a month with a minimum of three users gives each user a terabyte of storage, up to 50 file versions and audit logging, external authentication, and user management. All these versions also give you access to a wide variety of useful business apps: OneCloud.
Last, but not least, Box supports a wide-variety of operating system. There is not, I am sorry to say, a native client for Linux.
Dropbox is no frills cloud storage, but it works really well and it's really fast. Put it all together and that's been enough to make it the most popular personal cloud storage service of all. What I've already really liked about Dropbox is that I can use it just like it was any other network drive, with pretty much any file manager on any operating system. For example, in the screenshot above you're seeing Dropbox on Linux Mint with the Cinnamon desktop interface.
Dropbox's free version offers only 2GBs of storage. The Pro version will enable you to go up to 500GBs of storage for $499 per year. If you have a SMB, what you'll really want is Dropbox for Business. This runs $15 a month per user and an annual pricing of $485 and $125 a user a year after the first 5 users. The nice thing about this top price tier is that each account get unlimited storage.
Google Drive takes the tried and true Google Docs cloud-based office software and adds simple, easy to use file storage to it. Like Dropbox, it integrates with Windows and Mac file systems. I'm sorry — and annoyed — to report that, despite years of promises, Google Drive still doesn't support Linux. Enough already Google! Google Drive does, however, support Chrome OS, Android, and iOS.
Another nice feature is that Google Drive enables you to share and collaborate on any kind of file, including documents, music, images, and videos. In addition, Any content you create in Google Docs doesn't count against your storage quota.
Speaking of storage, Google Drive comes with 15GB of free storage. This storage space is also used for your Google+ Photos and Gmail.
The big feature of OneDrive, Microsoft's newly renamed SkyDrive, is its integration with Windows 8.x and Office Online. You can also use it with Windows 7 and up, and for OS X, iOS, Android, and Windows Phone. If your business is committed to Windows, then your choices will be between Box and OneDrive.
OneDrive comes with 7 GBs of free storage per account. With an Office 365 Home or Personal subscription you get an additional 20 GBs. You can also pay for more storage: for $25 annually you can get 50GBs; $50 gets you 100GB and for $100 you can add 200GBs.
There's also Microsoft OneDrive for Business. This enterprise-grade storage is not just an upgrade of OneDrive. It's built on SharePoint Workplace, which means Microsoft adds metadata to your OneDrive for Business files to make them more useful. There are a variety of plans. In each one every user account gets 25 GBs of secure online storage as well as 50 GBs for Exchange email. Microsoft is also promising that the minimum account will go up to a monstrous 1TB per account.
Let's say that while you love the idea of cloud storage, the thought of having your data naked out there somewhere on the cloud gives you the heebie-jeebies. In that case, be sure to check out SpiderOak.
Long before most people were worrying about the NSA, SpiderOak set up a cloud storage system where even they can't see what files you have in their systems or their associated metadata. Indeed, in its "zero knowledge" design they don't even see your password or encryption keys. Oh, and did I mention that your files must be encrypted? If privacy is what you want, then SpiderOak is for you.
Individual accounts start with 2 GB of free storage. Upgrades come in 100 GB increments, and cost $10 a month or $100 a year. The SpiderOak Blue business service starts at $600 a month, with a terabyte of storage for up to 100 users.
I can't tell you what the perfect cloud storage is because there's no such thing. It all depends on your needs. If you want ease of use, it's hard to beat Dropbox. If you want to combine cloud storage with workflow management, then Box is for you. Love Windows, then you'll love OneDrive. If you want just the basics, then Android Cloud Drive might be good enough for you. If security is the be-all and end-all for you then go straight to SpiderOak. And finally, if you want the most storage for the least amount of money or you're already using Google for most of your work, then Google Drive will be your first choice.
Me? I've used all of them at one time or the other and I've found them all useful. I'm sure you'll find one of these that fits your needs to a T.