Tomcat,
DP2 is sharper of course.
These 2 have been compared somewhere, I think. DP2 is good at some things, but also has other limitations.
I actually thought of buying another cheap E-P2 one day to experiment and getting the anti-alias filter removed, by these guys ->
http://www.maxmax.com/nikon_d200hr.htm. Then it will be like a Leica M8.2, M9 (or DP2), no anti-alias filter.
However, it doesn't make sense at will as it will cost around USD 400++, and I'd rather have it designed from the ground up by the manufacturer. I'm fine with the sharpness of the E-P2 with its already weaker anti-alias, and where an investment in higher-quality lenses will pay off, less sensor-limited (read that somewhere

).
.