I agree. In a simple office PC with a few data to backup and less than 10 applications to reinstall, a clean installation seems ideal. But for the average home PC with tons of data to backup and many applications to reinstall and reconfigure it looks like nightmare! So upgrade first and IF you have any issues, then backup your data and do a clean installation. Of course to succeed in an unsupported computer, you must do it properly, for details see the relevant sticky thread in Elevenforum. If you just go blindly to upgrade without having a clue, then yes, it will fail, and yes you will have issues. "One who is in hurry (and just run without watching where he is going) will trip", as we say in Greek.