I've thrown balls with both, an Eraser PBT and X-Factor with Accu-Tread, and a Fired Up with Reactor.
The core's on all three of the balls were different so I think that makes big difference in reaction. From my observation, the Accu-Tread was slightly less than the Reactor as a coverstock. The closest two in comparison were the Eraser and the Fired Up. I would say my Fired Up was more skid-hard snap, while the reaction on the Eraser was a bit less snap on the backend. They were both drilled the same.
Now, I've never owned a Jolt, but I've heard many good things about the entire line of Jolt's and I believe it would fit between the balls mentioned, but it would be a tight squeeze. Maybe talk to your pro-shop guy and go with a less aggressive drilling than your Onyx Vibe.
Chris Orgeman Get MOTIVated and Bowl Up A Storm!