I really struggle to see what exactly people see in Chabal. Seriously, big and strong ball-carrier, makes the occasional admittedly huge hit, but absolutely no finesse on the field.
Dallaglio in his prime was light years ahead of the current Chabal. What you got with Dallaglio was 200% commitment, unlike Chabal`s Oscar-winning football dives. You also got an intelligent player who could be equally effective playing towards the ball, as well as into space. With Chabal, you generally get the shoulder braced for contact, seeking out the nearest defender to run straight into. And in terms of Chabal`s only real strength, his physicality- well Dallaglio in his prime was every bit as physical, if not more so.
So basically, Dallaglio by a country mile really. Although I`d take Zinzan in his prime over either, every single time.