I will say this much: if you liked the X-Factor, you'd probably like the Gravity Shift.  The type of motion I see out of the Gravity Shift really reminds me of a stronger X-Factor.

If you want something to handle a little more oil, I am very impressed by the Dimension's reaction.  Lots of margin for error on a house shot and tons of continuation when it starts to hook.  On medium to medium-heavy conditions, the Rapid Fire solid will be a little longer and more angular, and the Rapid Fire Pearl is very long and angular, good for when you need to create backend angle for playing deeper lines.  And if you want something for when the lanes are a little drier, the Street Rods are both very smooth and controllable, and pretty cheap to boot.