A number of people have commented that ACR does not produce the most detailed files, especially when compared to Canon DPP or even the old RAW Shooter, with all sharpening tuned off.
I've done conversions comparisons in DPP, Capture One, Lightroom, RawShooter, Bibble, BreezeBrowser and ACR. For me, I found ACR and Bibble seemed to extract the least detail -- at least from the test image I used. And every single one had it's own interpretation of color, even using a gray card (actually I use an Expodisc). It's like shooting the same subject with Kodachrome, Ektachrome, Fujichrome and Agfachrome. Each film had it's own color rendition, grain structure and accutance (sharpness/edge contrast) and resolving power.
The beauty of RAW converters is they improve and I've found I can re-convert an older Canon 1D shot and squeeze out a tad more information. In the end, work with the converter that is most comfortable to work with. For me, that's currently Lightroom -- back that doesn't preclude using one of my many others if I feel it will do a better job with the shot.
