I recently downloaded the Windows 7 Beta.  I then proceeded to have no problems installing this on a rather old Dell Pentium 4 computer with 2 GB or RAM.  This was actually one of the easiest Windows OS installations I have ever completed.  So far, so good.  No errors and it seems everything works fine form my simple vantage point of a quick walk through. 

Then again I have had no problems with Vista other than the inability to run a couple of games that I never expected would run under Vista.

The only thing I have noticed so far is that Windows 7 works fine on some older hardware that failed to support Vista. This could be good news when Windows 7 is finally released if they do not bloat the product any further.