The Japanese Impress DC Watch has published a shootout of the above for a single scene, with quite a number of different combinations of ISO and NR settings, which is quite interesting:-
http://dc.watch.impress.co.jp/docs/review/longterm/20100422_362935.html
(Or the English Translated Page Here)
Do note all the differences and compare, measurabate, observe and make up your own conclusions by yourself. I again let you to do your homework and decide yourself and I won't spoil their test and results here (and better to save some of my time, too :-)) Enjoy!