MirrorFolder can make a real mess of your system if you mirror your boot drive. Just don't do it! Otherwise, it's not as good as the publisher says but it's the best option for fast backups.
You say MirrorFolder can make a mess of your system if you mirror your boot drive, but would you be willing to include supporting arguments, experience, or other specific facts? I'd like to understand why you make this claim. It sounds like you have some real-world experience with a failure. Thanks!