Originally posted by Lord Lucan
Cloud data is not secure. At best I would use it as a back-up for my own storage regime (but I don't) and it is certainly unwise to use it as your only form of storage. .
To prevent heartache, Lord Lucan, you need offsite backup of some kind. If thieves take your computer or your house burns down, the USB drive plugged into it goes too.
Cloud is instantly more convenient for me that it's worth paying for rather than the alternative - a routine of swapping USB disks that I'd keep in sync and then take to store daily or weekly or whatever at my place of work or a relative's house.
If security is an issue (either you're paranoid or have a commercial/professional interest or genuinely private stuff or whatever) you can use third party encryption as a wrapper over your files before you replicate them to the cloud.