I just started using SugarSync. I got a 10GB free account with my Kaspersky Internet Security 2010 purchase, which made me start using it. I compared it to Mozy Pro and it's quite a bit cheaper. Mozy Pro is basically 50cents/GB per month, which is obviously much more expensive than the cost per GB of an external drive, and much more expensive than SugarSync, where I can get 30GB for $5/mo. The performance of MozyPro is probably unmatched, however, which is why they charge more and target it for businesses (that have backup windows). MozyHome claims unlimited capacity for $5/mo, but it's billed per computer, so in my case, with 2 main computers that need to be backed up, it's twice as expensive, whereas SugarSync just charges you for the GB you use. Which service is ultimately cheaper depends on your usage patterns. SugarSync keeps the last 5 versions of your files, which you can access from any place you have web access. The software itself is awesome. It's got a good client that's quite streamlined. It doesn't use a lot of resources and setup is a breeze. It creates a "Magic Briefcase" in your My Documents folder. Any documents you put in there are automatically kept synchronized across all of the computers you have the client software installed on. If you want to sync other stuff, it's easy to do. From the client you can pick and choose which files/folders to keep backed up. You can access files from any computer on any other computer, which you give names and icons from within your account. There is also an iPhone app that works with the service. I now have access to all of my documents on all of my computers from my iPhone. Depending on the file type, I can view them or send them in email from my phone. This finally enables me to have a no hassle way to access my technical e-books from my phone, as well as anything else I might be working on. It can also take pictures from within the application and upload to the service so that they are immediately available from your other computers. The only downside is that for large transfers, it's kinda slow. Your initial sync, depending on how much data you upload, will take a fair amount of time. After that, you don't really have to worry about it too much. Most home users aren't modifying massive amounts of data on a daily basis. MozyHome suffers the same problem of low transfer speeds, but you get what you pay for. With the Mozy Pro service, you get way faster speeds, but at much higher cost. Anyway, most people don't need more than 30GB stored online. For instance the only stuff I have that is truly irreplaceable and worth paying for online backup of are my photos and certain documents. Everything else can be backed up once every couple of months to an external sata drive and stored in my safety deposit box.