I am experimenting with the beta 2 profiles and the Profile Editor. Currently, I use up-to-date CS3 and Lightroom 2, with CS4 in the mail. After individually applying various beta 2 profiles to an original DNG unaltered image of a stream taken in Colorado, the result was not as vivid in color as I remembered when taking the original.
I then took a profile (made in the Adobe PE) of a MacBeth Color Checker taken from a captured image in Arizona sunlight. The Macbeth color checker preset (in AZ sunlight) clearly improved the color rendition of the Colorado image much better, even thought the lighting environment of the two images were not the same.
Is it possible to predict an outcome such as this? I did not have a Color Checker image of the Colorado stream.
Relative to the DNG profiles for my own camera, I would have described the resulting color as "colorimetric accurate", which isn't what I would expect from my in-camera JPEG engine and was a bit too flat. All I did was open a DNG into the DNG profile editor and kicked the contrast just a tad with the tone curve and then saved the profile with an appropriate name.
Just how well the DNG profile works with your images is very much dependent on the white balance also being accurate. That is, I wouldn't expect anything more from your profile than my own experience, all relative to accurate white balance. Short of you being in very strange lighting, you shouldn't need a profile for all situations, only strange lighting, and always make sure your Wb is accurate.