I am a Campy fan too, and I ride a full Chorus setup. However, the one piece of Shimano I'm beginning to appreciate is the freehub. It is much quieter than the Campy, almost silent. I only tried putting my Shimano wheel on my bike last weekend and didn't remember it being so quiet, but with my Vento wheels there is no comparison. And in comparison to the very positive feel of the Campy shifting, the shifts are smoother on the Shimano wheel and you almost don't feel it. I'm still playing around with this, as I just replaced my 9speed Shimano cassette with a 10 speed tonight, I haven't even tried it yet. I want to see if the spacing will work better. I'm doing this without resorting to a shiftmate or conversion cassette, so there is no guarantee it will all work. And just to reiterate, I'm doing this with an otherwise all campy setup.
I'll basically agree with everything else said here. I've already rebuilt a brifter after a crash, the multiple shifts make it possible to easily go from small to big chainring with one smooth motion in each hand. The trim works. And I can downshift (or is it upshift? from the drops even though I have small hands.