The Hawgzilla and Pain aren't even close in ball reaction. Drilled both balls 4 x 3, pin under the ring, 35 degree tilt... identical layouts, so I could get a really good look at them.
Pain is MUCH "flippier" at the breakpoint. The Hawgzilla gives you much more of the typical Zone-type roll, early and smooth. I personally like the Pain much more because the surface can be altered for more of a variety of ball motions and it never seems to "hang" at the breakpoint.
On the pass-around, the heavy handers liked the 'Zilla more because it was more predictable and continuous, while those of us who are more rev-challenged, like the sharper change of direction that the Pain provided.
Hope this helps!
Jim
KKPS
CCPS