Have you read the Important Topics in all of the forum categories?

Well, it's always safe until something **** up :)
If you read stuff and understand what's happening behind what installers make appear effortless, you should be more than fine, having the confidence and know-how to reverse bad changes, if you're on your own.

I'd say the litestep installer is reliable. As for "safe", we get the occasional outcry from someone who claims he/she was forced to reinstall Windows as a last resort to some problem that could not be fixed.

Also do a search in the General forum for 'reformat' :)