Personally, I LOVE my Zero Gravity. It's a perfect medium to medium-heavy ball. I actually used mine to replace my IQ Tour Solid. When thrown side by side, the Zero Gravity is just a touch longer than the Tour, and it's much more continuous. When I threw the Tour, I always felt like I was playing defense. When I throw the Zero Gravity, I am in attack mode even if the conditions are tough.
I think the "problem" with the Zero Gravity was the difference between expectations, which are largely fueled by marketing, and reality. The Zero wasn't an oil monster like the Nano. For me, it was actually very similar to my old Special Agent. In any event, if you can get one at closeout prices, I would recommend giving it a try as your benchmark ball or maybe just one step above it. From league patterns to 1 to 1 ratio Sport patterns, I've found my Zero Gravity to be much, much more usable than a lot of other pieces in my bag.