Every time I swear off urethane, I talk myself into buying a new one.
With my medium rev rate, except for very rare conditions, I almost always find resin to be a superior option. Still, I currently own a Roto Grip Hot Cell, Black Hammer, Purple Pearl Hammer, Blue Hammer, and a Storm Mix (my spare ball). In the more distant past, I also owned Lane#1, Storm, and older Hammer urethanes.
As far as "old" or "new" urethane, my experience is that you'll never mistake any of the referenced balls with a reactive resin reaction. Even the Asymmetric Hot Cell with it's bad boy core is still a very recognizable urethane reaction.
I just got my Purple Hammer drilled up for a big tournament where there will be a short 35' pattern. I wanted a pearl urethane for a different urethane look, and in the few games I've practiced with it, I'm not disappointed. It clears the mids better than my Hot Cell and Black Hammer, and while not a "resin like" reaction when it hits friction, it has better urethane recovery than I'm used to seeing.
Scoring in the modern game is all about carry, so I'm perplexed by anyone with less than 400+ revs who would consider urethane as a first option. But the beauty of bowling is that we're all different and there is no single way.
