So Microsoft had an about face as regards releasing 8.1 early to TechNet and MSDN subscribers and made it available for download on 9th September.
I've now downloaded it and nuked my work PC so that I can get some out of the box impressions, rather than try the update route for my existing Windows 8 installation. Initial impressions are that the interface is a little more cohesive, but I'm not entirely sure that those that have been complaining about Win 8 will really be any happier.
There's the much talked about return of the start button, but this really doesn't do anything of note as it just returns you back to the 'Metro' interface. This was what happened anyway if you clicked in that region of the screen, so no real change there.