Stay away, the reason? read this article:http://www.techarp.com/showarticle.aspx?artno=407
Then get my advice as I my self bought an ES (an E6400 actually) and the article is right. It would not overclock beyond 3.3GHz at all, although many more could get it at 3.6GHz quite easily. Also it came with the normal 2MB of cache instead of 4MB that some people got with their ES.
At the end of the day it is a NON STANDARD chip, with no guarantees and no warantees. It means that if you get it and runs at 1GHz and one core, you are stuck with it! STAY AWAY!