Just downloaded CaptureOne LE. So far I think it is a mixed bag. I'm converting images from my Canon 10d and comparing them to Adobe Camera RAW (with the hack). First of all, Adobe is about ten times faster.
The C1 images seem smoother and the color more natural, BUT there is less detail overall and, most important, CI seems to have blownout highlight details. I've played with the settings but still find that Adobe holds detail better in the highlights and images look less blown out around spectral flares. In my view, blown out highlights is the biggest drawback of using a digital camera so this is enough of a reason to stick with Adobe Camera RAW. I also wonder how much better Adobe Camera RAW will be once they update the software to handle the 10D without the hack.
I'd provide a sample image but I'm not sure how to do that on this forum. If some one will be so kind as to let me know how to do this I'll post samples.