It's unlikely that there will be noticeable degradation of the signal when using quality component cables. In fact, a little degradation can sometimes hide compression artifacts at the expense of detail. In most cases, you can't send a 1920x1080 progressive signal through component cables because of HDCP, so the HDMI cable would likely win out in that scenario. You can send an interlaced 1920x1080 signal through component with no problem, and you can sometimes find equipment willing to send 1920x1080 progressive signals through component.