A while back, I stopped using Carbonite . My PC was misbehaving--its performance was terrible--and it was easy to blame Carbonite for at least part of the problem. Carbonite's style is that it constantly monitors your Windows file system and makes backups almost immediately when a file changes. That's good if you want excellent backup protection, but it sucks CPU, file system performance, and bandwidth from your PC. Most people won't notice the performance drap, but on my old PC, it was intolerable.
I switched to Mozy, and I've been happy with it. Mozy's style is less obtrusive. It runs once a day, waits for your PC to be relatively idle, scans the file system for modified files, and backs them up. It's not quite as safe as Carbonite, but it's good enough for me.
I strongly recommend Mozy. Sign up for a free account and get up to 2 GB of backup at no charge. Or sign up for Mozy Unlimited Backup for, yes, unlimited backups. Yes, those are affiliate links. If you sign up for Pro, I'll buy you a beverage at my local pub.