What sub for Watt/Puppy 7? - Watchdog vs. WHOW

I currently have a Watt/Puppy 5.1 and the subwoofer WHOW III with the Krell crossover. I'm interested to go to a Watt/Puppy 7.
With a W/P 7 should I still use my WHOW or should I replace it with a Watchdog?

Wilson recommends the Watchdog as best fit for the fast W/P 7, because of greater flexibility and speed.

Anybody did this comparison?
How does a topclass Velodyne perform in comparison to the Wilson subs?