No, it wont replace the System Restore in the way that you can use it to Roll Back. But maybe the question is not if it will replace XP System Restore or not, but if System Restore is worth anything to you. XP System Restore has been worth nothing to me, and you told that System Restore never worked for you. So there you have it!
But do remember that Erunt only will backup the registry keys. Each time you delete a program / anything, the backup cannot recreate such. If you want a genuine Roll Back option, you will have to create Images
of the entire PC. Erunt cannot do that; it will not offer you the chance to roll back if you have deleted the wrong file or the wrong program, only the chance to recreate the registry - and for this it will need the original files to be present. I have learned the hard way to keep everything, until the PC have been working for several days with any new programs / updates. Don't empty your basket too soon!