Which is better, the Prescott 3.0E D0 or E0?

I'm currently OC'ing a Prescott 3.0 E0 to about 3.8 dual prime stable. My roommate is current OC'ing his 3.0 D0 to around 3.7 dual prime stable. we have very similar setups with the same cooling system. Which Prescott stepping will result in a higher overclocks?

Depends on the setup but in most cases the EO is going to OC better.

On average, the E0 overclocks a little better, but I've seen a few exceptional D0 steppings do really good too.