I did a comparrison of Lightroom 1.0, Aperture 1.5, Adobe Camera RAW and Capture One 3.7 in terms of RAW processing just to see which one was best and found that, in my test and opinion, Capture One gave the best result with Aperture a very close second and Lightroom (due to it's cost over ACR), a distant fourth My Article Here
I've now just completed another test using Aperture 2.0 and Lightroom 1.3 and again Aperture does seem to be better at RAW processing than Lightroom. However Lightroom 1.3's new sharpening algorithm is vastly superior to that in 1.0 and better than the one in Aperture 2.0 by quite a margin article can be seen here
I'd still much prefer to use Aperture over Lightroom but I might be tempted to use Photoshop CS3's Smart Sharpen filter to get the sharpness that could be achieved with Lightroom on it's own.