Mini Review!
LiveDrive
Pro: Simple set up. Nice GUI and website
Cons: Stupidly, absurdly slow upload
If you have all year or not much to back up, then this will probably be quite good. If you have anything remotely sizeable, don't bother. The best upload speed I got was 600KB/s average was around 200KB/s. Hardly making use of my 7-8Mb upload.
Crashplan
Pro: Lots of backup options and locations
Con: Slow upload speed.
This has better upload speed than LiveDrive, but it struggled to get up to any kind of decent speed. For a while it was at 1mb, which is pretty damn good, but would regularly drop to useless speeds. It was quoting well over a week for "just" 50GB.
BackBlaze
Pro: None
Cons: Awful GUI, awful website, awful installer
Wow what a piece of crap. First it was the only one that wouldn't install on my server OS, so had to install it on my desktop. The installer is buggier than the underside of a rotting log and the program crashed twice before I could get anywhere near the settings.
You also HAVE to backup your C:\ drive, regardless of what you may actually want to backup. I never tested the upload speed because I couldn't even get it to back up what I wanted it to backup.
Carbonite
Pro: No idea
Con: GUI, speed
Awful, awful, awful GUI. A third-degree burn would look better. Upload speed is woeful. Took it 30 minutes to upload a 50MB file.
Conclusion
If I had to pick one, I would go for Crashplan, since it seemed the most consistent with upload rate, and also had the highest speed. GUI is nice and easy to set up. The rest I would toss out the nearest 10 storey window.