How many of you use a cloud storage service like Dropbox, Sugarsync, Gdrive, Skydrive, Box.net or any other similar service?

Why you use that service? Any special feature which lets you stick to it compared to other or its just the free storage?

If you do not use any of these, what are the reasons? or perhaps you don't need it at all?

At the moment, I am using Sugarsync and dropbox.

Sugarsync is being used more by me due to the simple reason that it lets me choose the folder for synchronization instead of a single folder like Dropbox.