Let me clarify the comments above, the ball strength is relatively close on paper, the GB2 is earlier by a good margin. I use these 2 as different shapes and strengths, my Sideswipe Solid has a shorter Pin-PAP layout and less surface. M GB2 has more surface usually and a little longer pin-pap layout. Think of them as different shapes, not as much different strengths, Where the ball reads in the midlane is a much bigger deal than how strong it is.
I have both in my bag for tournaments. I have tried both pieces at pretty much any surfaces. Surface is the major factor in ball motion these days. Surface determines length, layouts, pin placements are down the list. Surface is #1 by alot, #2 is pin-pap distance. these 2 things make up 75% of ball motion characteristics.
The phenom pearl is another good Gamebreaker series piece, although I have Affinity which is similar.
If you want something stronger downlane than the phenom pearl, take a look at the Rhodman Pearl, probably the hottest selling piece right now.
Its plenty clean up front and plenty of motion downlane, but not the jerky hockey-stick motion, just more of an arcing motion, great rolling piece