This is how I feel as well. DC has the best rain and lighting effects (particularly from the sun) in any racing game. When it positions itself to put these effects on display, it is really incredible.DC looks better no doubt, but the only time the real disparity hits is during rain effects masking their environments. Their rain effects are downright crazy good looking, everything else is average to insane.
However, in pretty much every other area it is just okay. In particular there were a few night races I tried (no rain) where everything just looked flat and somewhat dull. If you want to focus just on the highlights of DC then it does look incredible, but it does not maintain that level of graphic fidelity throughout.