this has been released to the public and is available from windows via the automatic updates if a patch is installed - details here

http://www.microsoft.com/downloads/d...displaylang=en

its still beta - so I am not recommending this, but the inclusion of it in the update programme probably means final release very soon..

there are reports of around 10% increase in speed/performance

I am not in a position to measure this - but I have been running SP3 RC2 for several days now, and the whole system is a lot smoother - radio streaming and realplayer 11 performance is better - the difference in quality and stability noticeable.
Not noticed any problems - but I don't game or push the envelope OS wise.

Was also amused by reports of Vista as 'Windows Millennium II' in certain quarters... when considering the implications of Vista SP1... but I don't run vista so for all I know that's just flannel...