My initial experience wasn’t that great. My initial backup failed, and since it takes so long to transfer a hard drive’s worth of data over the Internet, I gave up on it for a while, intending to troubleshoot on a free weekend. I think the failure may have had something to do with my 100 GB hard drive being nearly full. As far as I know, the initial backup needs to be completed all at once, so if it fails at any point, you have to start the transfer from the beginning.
After booking my trip to Vegas at the beginning of this week, I was reminded of the fact that I own a Time Capsule there, and it was about time I put it to use. So I tried it again, this time with my lighter load of about 70 gigs. It took some time (a couple of days), but the transfer did eventually finish. Now, everything seems to be working just fine. It’s connecting to the server automatically and backing up every hour. The backups are a lot slower than connecting directly to a drive via FireWire or USB, even if you’re not transferring much, but since it happens in the background, it’s not a big deal.
The Time Machine interface itself (which you use for restoring files) works over the network but is pretty slow. If I ever do need to use it, it would probably be a complete disk failure and in that case I’d just have the Time Capsule shipped to me.
I think the service is a neat idea, and it’s working fine for me now, but unfortunately with the speed of today’s Internet it’s not quite the solution I was hoping for. If you’re considering this for yourself, I’d suggest just using Time Machine with a local Time Capsule or other backup disk for your immediate backups, and keep an archive of your backup off-site (at your office, etc.), updated every week or month.