1. The Slingshots never hooked as much as the pearl Power Grooves because the PG had much a larger RG differential. There were several varieties of Power Grooves including solids and Particle Pearls. They are much different than the "plain" pearls. Slingshots only came in pearlized PK 17, except for the Pink/Purple one which used a different coverstock (Activator, I believe).

2. The Slingshots hardly hooked at all. It was one of the closest resin balls to urethane that I have ever thrown and I am rev dominant.

I have been a big fan of both. The Slingshot will have the newest version of PK17 so it may be a bit more aggressive cover then that used on the Power Grooves.

When comparing the Slingshot with any power groove using pk17 I have found the power groove to be the bigger hooking ball. It has a much larger differential and also a higher intermediate differential.

The PG is an asymmetric core ball because of the two hook pucks in the bottom actually being off center. I have four of them currently undrilled in my closet that were spun on a determinator. The PSA ended up being in line with the pin and cg on all four bowling balls. However the pin was actually on average 1" to almost 2" further away then marked.

So something to keep in mind of you buy a power groove.

Either ball can be a good choice depending on your style and the lane condition along with the layout chosen.