Thanks for the opinions guys...on the subject of 'over-under' however, I have a few thoughts of my own. I feel that these days it is rare to find a ball that is 'over-under' as a characteristic. I think rather, that it's a matter of using balls on the conditions for which they were intended AND adjusting the shell accordingly.
I remember when we first began to drill Gold Rhino Pro balls and were finding that they were what we called 'over-under'. They were darts on oil but hooked more than anything I had ever seen on dry. I got a hunch that the shell was too polished for our lane conditions and began sanding the factory polish off and re polishing with whatever we were using back then, probably finesse it. Anyway, the results were very positive, it was more consistent and didn't hydroplane as badly when tugged into the puddle in the middle.
Since that time, I have sanded the factory polish off several balls that I was afraid might be likely to have the same problem and I feel it has been very useful.
In terms of balls that I did think had some over-under tendances to them...I can think of one right off the top and that is the TPC Shooter. That was the only ball that had that core design that I actually tried but it seemed to me that if I came around that ball even slightly more than the previous shot, it reacted much stronger. Just not a forgiving kind of ball in my opinion. I continue to use it but I try to stay away from the outside part of the lane if it's dry out there because that was where I was getting into trouble.