have been using iDrive now for several years – excellent value for money $49 yearly for 150GB of space:
+ points are :
i) Mapped drive backups ( ie not just local drives but network drives)
ii) Incremental Backups
iii) Access to backup set from anywhere via a browser if needed
iv) Good chat based support

- points
i) can be tricky to get it to run as a scheduled process to backup network drives – is my experience which could be influenced by the fact I am running a a Linux/ Samba based file server infra-structure
ii) No native Linux client