This software runs pretty good and is basically "hands off". I am running Windows XP Home 32bit. I like the Explorer interface for viewing and copying files stored on the backup drive. It will also tell you how many file versions are available. It appears to use services to do all of the dirty work in the background. Nice little widget in the system tray at all times for quick access or status.
Some things I noticed:
1. You can not restore to a drive smaller than the drive that was backed up, even if the backup will physically fit on the smaller drive. This is the only thing I really don't like about the software.
2. This software backs up created/modified files on the fly. I have a triple core CPU and 4GB of memory, so it really doesn't affect me most of the time. I only seem to notice some lag when the machine first boots as it performs a backup right away, so grab some coffee as it will take a few minutes to calm back down.
3. It creates a recovery point every 24 hours after the last recovery point. If you don't want this heavy activity to impact you, I suggest staying up late one night and kicking one off manually. Mine usually runs around 2:30am. Since I leave my machine on 24/7 it generates the recovery points while I am sleeping.
I think Rebit is pretty cool stuff and reminds me of Apple's Time Machine. Some experimentation and patience, along with decent hardware, and you should have few, if any, problems. I have a 250GB external USB 2.0 hard drive dedicated for these backups. I spent the first couple days testing and learning, searching and reading the Rebit forum, uninstalling/reinstalling the software, formatting the backup drive over and over again, until I felt comfortable with it all.