Test three - Data retrieval
Uploading all your files to a remote server is great, but the real test is retrieving them if you ever have that disastrous flood or your computer is stolen.
The best service here in terms of flexibility is the plan from Backblaze. Not only can you download your files in a ZIP archive, you can have your backup shipped to you on DVD or USB. This is great if you need to get your data back in the fastest way possible. Naturally, you'll have to pay for international shipping on top of the $99 (£63) for DVDs or $189 (£120) for a 400GB hard disk, but if you're downloading a lot of data it's likely to be much faster.
The rest of the services here offer online retrieval tools. Carbonite is next best, with its Restore Assistant that manages all your file retrieval automatically. You can still pick and choose which files to get back manually if you want, but if it's a full restore the assistant takes the pain out the procedure.
Each of the rest offers simple online file restoration tools.
Test four - Extras
The main process of backing up your Mac is clearly the most important aspect of each of the tools, but those hidden extras all add value.
We really like the flexible CrashPlan approach that enables you to back up to any remote computer. This allows you to create your own off-site backup. Save your work computer's documents to your home Mac and vice versa. It alone makes the client incredible value for money. Also its Backup Sets can be split between online and local storage.
The Livedrive Briefcase feature lets you email documents to be synced across your machines, and you can access your files from an iPhone too, as well as streaming any music or video you have stored online. Simply install the Livedrive app and you can be watching movies on your iPad without taking up that precious disk space.
Backblaze, Carbonite, iDrive and Mozy are less expandable in comparison, offering just the simple backup tools.
The Winner - Best online backup service for Mac
All the services here work well if you've only got a modest amount of data to upload. No matter which one takes your fancy, the end result will be a reliable and safe backup, and that's all that really matters.
iDrive is a touch pricey by comparison to the others, but the rest are all roughly equivalent. We liked the invisibility of Backblaze and Mozy, where the clients are unfussy and just get on with the job at hand.
But ultimately, our winner is CrashPlan. It's solid, easy to use and reliable. It also offers the most flexible client with the best extra features. The $120 (£76) family pack feature is amazing value in comparison to the others on test here too. As such, it fully deserves our top spot.