How does Creo 4's updated ISDX compare to CATIA's latest ICEM Surf?

From the 3DS website "For more than 25 years, ICEM Surf has led the world as a software solution used for Class A-surface modelling". That may be true, but ISDX is surely more competitive now that it includes G3 curvature continuity. The web seems a little short on thorough comparisons, and PTC seem to have been a little quiet on the topic.