Is it as straightforward as the manufacturer claims, and will my PC ever be the same again?
Yes and yes. But you may never be the same again.
No matter what you "backup" to restore to your newly-reformatted computer, there will always be a file or (an) email(s) that you totally missed and - Murphy's Law - can't be recovered from anywhere else.
If cash isn't too much of a problem, get yourself a large external drive and backup your entire internal hard drive on to it before you reformat your system (programs and all, but you may not be able to run them by just copying them back on to your new system drive - they usually need reinstalling).
And export all your emails on to the external drive in csv format. (You may even want to write down your email account settings so that you can easily set up up your accounts next time).
Good luck.