I think the comparison stops with the fact that both are very good left arm spinners. As has been said, Vettori has a very intelligent cricketing Brain and when he takes over from Fleming as the Captain, is likely to improve his own bowling performance (like Benaud did after he became Captain) by strategic use of NZ's available attack, including himself. Panesar is a very good bowler with a potential for future greatness, but he needs the guidance and support of a good captain; otherwise, he could lose confidence in himself after a few below par performances.