My Special Agent was my go-to ball for ages, but I have since replaced it with the Dimension. I've only had the ball for a couple weeks now, but absolutely love it. It's like a Special Agent on steroids, a slightly more angular version of the Cell. Absolutely amazing ball. The Special Agent is great too, but the Dimension just takes everything I liked about the Special Agent and improves upon it.
I bought a used Gravity Shift from a friend and have only thrown about one game with it so far, so I don't have much to say about it yet. The one game I did throw it, the lanes had gotten absolutely trashed outside and I had the worst over/under look I've seen in ages (I had less room to miss than on a fresh PBA pattern!) with any equipment, so I can't really judge much off that.
