I have not used the software you mention here. However I use several different online backup solutions daily for my customer base. The only real problems with online back up are really large files. As the can get problems uploading, becasue the avarage internet connection has such a low upload.
The smaller the files the more reliable the backup will be. As the larger ones get curupt more easily as they are often intupted in transit and restarted several times before completion. It also depends alot on the quality of the software package. But in general online backup can be relied upone, my personal pref would be to use a more business aligned product such as the Attix5 solution which is provided/resold by the Risc Group if the data is critical;
http://www.riscitsolutions.co.uk/online_data_backup.html