Back in the old days of Windows 3.11, 95, 98 and XP, upgrading a system seemed a bad idea due to all the conflicts and instability that usually ensued. So I have created the habit of reinstalling systems whenever a new version was released (to avoid said issues but also to clean the filesystem of old DLLs and system files that would be left behind).
With Windows 8 we only had the option of upgrading (or getting it installed by the manufacturer) and the feeling that behind the shiny new interface, there was a mess of files, DLLs and other bloatware.
Now Microsoft has reintroduced full retail versions with Windows 8.1. Is it worth getting the retail version and reinstalling the system from scratch? The idea "feels" good but does it make sense nowadays?