Most of the software eschew standard Mac OS X selection and interface elements. Instead, they tend to stick options all over the place, often with inconsistent usage, and provide some truly baffling selection and restore interfaces. Menus are particularly misused.
Mozy scatters parts of its functions across several independent floating windows and programs, including the critical tasks of file selection and restore, and adds in a system preference pane to boot. SpiderOak's colorful front end looks nothing like a Mac app.
In iDrive, one menu reads Backup-Restore and contains two menu items: Backup and Restore. Clicking on buttons in the main window might change the display or bring up an informational message with no options. Jungle Disk, with the most fine-grained settings, has well-written explanations, but a design entirely its own.
Although we don't look for "pretty" in a program, we do value how quickly we can recognize and perform a task, how accurately that task is carried out, and how well we can repeat a task without having to relearn new behavior. CrashPlan, Backblaze, and Carbonite succeed best at hiding complexity behind a simple interface (although Backblaze and Carbonite have other significant limitations).
Selecting and excluding files
The biggest difference among all the hosted backup services is how you select files. Each program has its own rather distinct method for choosing files; most also offer a way to exclude files.
The most obvious starting point is selecting hard drives and flash drives. All of the services we looked at let you select any locally connected drive.
Several services also let you back up any network-mounted volume that's available via the Desktop. Flat-rate services except CrashPlan won't let you back up such volumes; iDrive, JungleDisk, and SpiderOak allow it. Jungle Disk and SpiderOak require that you navigate to the /Volumes directory to reach networked drives, a seemingly unnecessary step instead of showing those drives as available sources.
The idiosyncrasies really show when it comes to choosing files to back up. Backblaze only lets you select drives, and relies on an exclusion set up to remove items from the backup. By contrast, Jungle Disk has extraordinarily finely detailed settings and choices for both selection and exclusion. Several packages let you avoid backing up files above a certain size, too, which would let you exclude large files to avoid or ones that you archive elsewhere, such as movies and virtual disk images. Jungle Disk also lets you select files by wildcards and file type.
Mozy appears to be unique in using Spotlight both for preset selection options (such as all your applications' preferences) and allowing new selections based on a Spotlight search.
Excluding files is tedious in most programs. Almost all of the software we looked at uses a hierarchical selection method to choose a folder and all nested folders; some use a Mac convention of clicking on triangles to expand or collapse a nested item, others plus and minus signs. To exclude a nested item, you may have to click down several levels in some packages, find the item, and uncheck a box next to it.