My main working machine is Mac OSX snow leopard. I'm using also android mobile phone, android tablet and linux desktops. The big problem for using claude strage is supports for platform, public policy and size of strage.
Dropbox is one of the famous claud strage. The lient software for Dropbox has good functionality, even if it is free uses. However, Dropbox is weak for strage size. Yes, Dropbox has more than enough functionalities. And we can use dropbox for free. If you want to use larger strage size then you can pay. The size for free users can use 2GB. And you can pay for 50GB or 100GB. The amount of cost is not so big. But, it can make dammages for students life, even if it is small amount of costs.
On another hand, Box.net, N-Drive, SkyDrive and UbuntuDisk (I'm not sure the correct name?) are also good strage services what we can use for free, too.
My private opinion, Box.net is also good cloud service. Box.net can use 50GB for free. And Box.net has good web interface. However, the client for Box.net on mac osx is not good. Before version 3.0.1, the client didn't work on OSX (snowleopard). Now, it works on OSX. However, the client's UI is not user friendly. It is difficult to use. And for the synchronization between cloud strage and local strage, we need to pay every year as dropbox. I can say both of Box.net and Dropbox are good service and it is enough cheep cost for using there good services, if i'm working.... ^^;
SkyDrive is provided by microsoft. Users can use same account with hotmail. It is one of the good thing. But, my private opinion, same as Picasa by google, I don't want to upload my private and important data to there. Because, I'm not sure about the publication policy. I makes many mistake. If i will make mistake to setup the publication policy for my private documents..... However, they are good for uploading the photos. Especially , SkyDrive can be used 25GB of storage. it is more than good for web photo storage. And Google services can be used 1GB for pictures and 1GB another storage for documents. And, SkyDrive may not have client application for MacOSX.
N-Drive can access using WebDAV. For the accessing to use WebDAV, N-Drive is more stable than Box.net (this is before to be released ver. 3.0.2(box.net). we needed to access with webdav)
* actually, I didn't know about this. But, in the internet, there are two different N-Drive with similar service. My meaning is the service provided by NAVER.
This is good for android tablet, too.
Ubuntu one is similar service with Dropbox. We can sync data between cloud and local directory. But, it has weak for platform. They support only for Ubuntu, Android, iOS, and Windows. They don't support to OSX..... With out this point, UbuntuOne is also one of the good choice to use cloud data management.
Like as this, even if we have many cloud account on the ineternet. however, to use them with samething is difficult. ZeroPC can solve it. ZeroPC looks like online OS. The service can transfer the data from one cloud to other cloud. Current version is 2.0. The support cloud is following.
Box.net, Dropbox, Evernote, Facebook, Flickr, Google Docs, Instagram, Picasa and SugarSync
Now, it is not support for UbuntuOne and N-Drive. However, For free account. ZeroPC also have limitation for data transfer. We can transfer 1GB/ month. However, if we use Dropbox for sync with local and claud and to use ZeroPC as bridge then we have some other big claud strage. It is not the most convenient way and sometime we feel lazy about this way. We need to consider something about them. But, it is one way to use multiple claud on many devices.