One will test out better on the specs, but actually the results to the human eye are entirely subjective. Technically speaking AVCHD may be considered inferior due to its compression scheme although that compression scheme is highly regarded and becoming more widely accepted among HD enthusiasts, but again beauty is in the eye of the beholder between it and DVCPro HD on the screen.
It all really depends on what your final production intent is: DVD, BluRay, broadcast, cable, etc.
