The guys over at X-Bit seem to think that the E0 clocks better.
http://www.xbitlabs.com/articles/cpu...0_3.html#sect1

It's still luck of the draw though. There isn't enough evidence yet to say for sure but generally when Intel updates a processor, the overclocking abilities increase as well. There are some nice Revisoin C0 chips in this thread that are better than X-Bit's E0 at the same voltage.