First I would like to start by saying all of the below systems offer data encryption and redundant servers to make sure your data is safe. They offer good pricing and have comparable up-time guarantees. I have tried these systems out either by using them in my businesses or by playing with them to find out which one is the right one for me. All pricing was at the time of writing this article.
JungleDisk – I have used this service with a few of my customers. JungleDisk sets up easily on a Gnome or KDE desktop. I have run multiple installs on Cent OS systems. The system supports Amazon S3 and Rackspace Cloud Files storage. JungleDisk supports full encryption and will restart running processes if shutdown during backup or if a crash occurs. JungleDisk archives old and deleted files for later retrieval, and relies on multiple data centers to keep your files safe. After the initial set up costs which was around $50 the service is costing about $8.50 a month for one of my customers to back up about 50 gigs of data. Really a pretty good deal. Since I set the system up 2 years ago I have never had to make changes to the backup. I did have to restore about 100meg of files and that was very easy to do through the desktop application.
Memopal is based out of Rome, but they offer a cross platform software client for Windows, Mac, Linux and IPhone. You can install the software on more than one computer. They offer web and mobile access to your data and have a search feature so it is easy to find the file you are looking for. Selecting files for backup is easy and they even offer the option to backup your entire system. Personal plans start at $49.00 / year for 200GB. They do use a GUI and the Linux system is still listed as a Beta. The support is email based and they promise a response in 24 hours. Good value but a little vague in the Linux support.
DataStorageUnit is a relatively new player in the online storage world but they have a lot to offer the Linux world. DataStorageUnit is an offsite backup service that allows for lots of flexibility. It supports open protocols such as SFTP, RSYNC, & SSHFS … so you can choose to use our included partner software, or any other apps that support those protocols. Because you can use SSH and RSYNC DataStorageUnit is a very flexible solution. With a little script writing you can customize any backup scheme you wish. Great for command line only systems and headless servers.