I used it for a little while but do not anymore, it really does nothing more than any good backup software does when used correctly.
@pxxb1 is right , HorizonDataSys is usually slow on updating the software, while it will work on one Windows Build, after you update to a newer build the software may not work correctly until it in itself is updated, which unfortunately sometimes takes them time (according to my past experiences). I can remember going from Windows 7 to 8 , it took them months to update the software to get it to work with 8 , during that time the software on 8 was unusable, this left a real bad taste in their users mouths.
The software is clunky and will have an impact on your system while running, I'd advise against having it run in the background.
In my personal opinion , it is really not worth what they charge for it , even at a discount. Like I said , your money will be much more better spent purchasing some good backup software.
Unless your pc(s) are for public use or others other than you use the pc, there is no real need for "system snapshot" software , and if you are insistent on using it, there are ones better than RollbackRx.
I haven't visited their site in quite some time but they used to have a forum , if it is still there, It would be a good idea to read through it and make your own personal judgement .