Yes, the NDH 30 has better dynamics than the HD 600, but I have to tell you that 'dynamic and punchy' are not what the NDH 30 are about at all. The NDH 30 are about accuracy. Accuracy in terms of perceived frequency response, tonality (timbre), instrumental separation, dynamics, soundstage etc. To some, like me, who value accuracy, (I'm a pro musician (player) and I usually listen on pro monitors (ATC) ) they are the most exciting headphone to hit the market in years (that I'm aware of). To others they seem boring. If you're looking for a punchy and dynamic headphone then you may find yourself in the second category.
I will add though that the ace up the NDH 30's sleeve, is that they manage (for me at least, and I know that I'm not alone) to be musically engaging at the same time as being accurate. That's a rare achievement.