read this.
http://technet.microsoft.com/en-gb/evalcenter/dd353205.aspx

"January 10, 2009 (Computerworld) Microsoft Corp.
on Saturday restarted its rollout of the Windows 7 beta, 24 hours after
it aborted the launch because heavy demand had stalled its servers. As
of noon PST, the company said that the primary beta download site, an
offshoot of the Windows section of Microsoft.com, was "up and working."
Computerworld confirmed that the Windows 7 beta download page was
online and taking download requests. Springboard Series, another public download location targeting IT professionals, was also live. "

http://www.computerworld.com/action/article.do?command=viewArticleBasic&articleId=9125660

For me it looks far better than Vista. It works like charm.
download Link  for windows 7 :
http://www.microsoft.com/windows/windows-7/beta-download.aspx


If you need key to install then follow bellow article.:
"Download and Install the Firefox add-on Check For Change.
The add-on can be used to refresh a website in a specified interval. It
will stop that if the selected display on the website hanges.Sign In on the Microsoft Technet
Website. If you do not sign in you will be redirected if you try to
open one of the following two urls: (copy and paste the links, do not
click on them)
32-bit: https://www.microsoft.com/betaexperience/scripts/gcs.aspx?Product=tn-win7-32-ww&LCID=1033
64-bit: https://www.microsoft.com/betaexperience/scripts/gcs.aspx?Product=tn-win7-64-ww&LCID=1033

You will most likely see Error: The site is currently experiencing
technical difficulties, please check back in the next business day.Select the text, right-click and chose Check4Change, Check every 15 seconds.The Firefox add-on willl automatically refresh the website every 15
seconds. It will stop doing so once the display on the website changes.
You could do this manually but some users mentioned that they refreshed
the website for hours before receiving a product key."