XDrive promises to mount a virtual drive to your PC, allowing you to copy and paste files to that drive just like any other storage device. Once files are copied to the virtual XDrive, a behind-the-scenes engine promises to upload the files to a remote server. At least that's how it happens in theory.
In reality, XDrive often failed to mount at all when I used it. Even when it did mount, the behind-the-scenes file upload engine would often leap to 98% CPU usage, hogging nearly all system resources, and refuse to go away until I hit CTRL-ALT-DEL and chose "End Process" to shut down the XdrSmb.exe application. In terms of software applications, XDrive is what I call a "misbehaved system hog." And I know what I'm talking about with software, as I own a software company that's been in business for thirteen years.
Even when XDrive happens to start uploading properly, it sometimes mysteriously halts the upload for no apparent reason, even when other processes (like FTP from a different application) are working just fine. I could not find any apparent way to restart a failed upload with XDrive.
On its website, XDrive claims to offer "24/7 support." But it isn't support, it's just a user guide and a forum. That's not 24/7 support. To get actual support, you have to call their offices during business hours.
You also have to call to cancel your account, apparently, because I could find no way in the account management area to actually cancel your account. The only option available is to upgrade your account or pay for a full year. So they can take more of your money with ease, right there in the account management area, but they won't let you cancel until you call. I also tried emailing to cancel my account, and I haven't heard back yet. This may end up being one of those times when I'll have to dispute the charge with American Express.
The bottom line on XDrive? Steer clear of this one. In my opinion, it's a system crash waiting to happen. And besides, it rarely worked right, at least on my PC. It's no surprise this service is owned by AOL (which is also famous for making it difficult for people to cancel their accounts).
Box.net claims that with the right Java, you can drag and drop files to be magically uploaded. I did not find this to be true. Even after upgrading to the latest version of Java, rebooting, and re-launching the Box.net service, every time I dragged and dropped files into the Box.net destination folder, my web browser got confused and thought I was trying to download those files. If I accepted the download, then my own files were copied from their original location to my download folder, which of course, is something I can do all by myself without Box.net. And it does nothing to accomplish the goal of remote backup. But it does make Box.net the most expensive and inefficient local file copy utility ever.
Thus, both XDrive and Box.net failed to work for me. Neither seems ready for prime time. Perhaps a new remote backup solution will appear in time, and I'll be glad to give it a whirl, but so far, I haven't found a remote backup solution that really works.
For now, your best bet is probably to buy an external hard drive, copy your files to it, and mail it to a friend who can keep it in a safe place. It's reliable, easy to figure out, and there's no monthly fee involved.