Of the two applications in the first category, both have positives and negatives. Backblaze does a thorough initial backup but doesn't offer mobile apps that let you grab files from a smartphone while you're on the go. In contrast, Carbonite has apps for iOS, Android and BlackBerry devices, but it is the most expensive service that I looked at.
Three of the five backup services that I looked at could copy the entire hard drive to online servers, but they differed in many ways. Norton Online Backup lacks recent creature comforts, like the ability to augment online services with a local backup on an external hard drive. By comparison, CrashPlan seems to have it all, but its full system upload at more than four days was too slow to be practical.
That leaves Mozy Home as the winner. It may not be perfect, but it offers a great mix of economy, security and features. I just wish that it kept deleted files forever.
How we tested
To measure how these online backup services compare, I downloaded each application and checked out its features. I performed backups and updates and restored a variety of files on an Acer Veriton M4 desktop PC with Windows 7 Professional. I began by backing up the system using Norton Ghost 15 with a LaCie 2big USB 3.0 external hard drive.
After getting familiar with the service, I timed how long it took to perform an initial backup of the system using the service's default settings. I noted the connection speed and how much data was moved. Because the amount of data varied depending on what types of files the application handled, the timing here is more a point of information than a way to compare the services.
If the application supported it, I then did a full backup of the system's C: drive -- a total of 35.4GB of data.
To see how each handles new data, I added a folder containing 25MB of assorted files, including images, video and Office files, to the system. I timed how long it took to make the incremental backup.
To mimic what happens if data is lost or corrupted, I then deleted a 10MB WMV video file and timed how long it took to search for the file with the online backup system. Lastly, I timed how long it took to restore the lost file.
When I was done, I restored the system to its original specs and repeated the sequence with the next service.