I just purchased a twitch, after 2 weeks of debating getting that or a native instruments controller.
I am OS x 10.85, not mavrick.
I've talked to 11 other twitch owners who all have the same problem. The usb drivers do not work, no lights, computer doesn't recognize that it's plugged in. I've tried all the silly "fixes" like trying a different usb cord, reinstall the drivers 20 times. It's definitely not a hardware issue because i've gotten it to work twice through a work around I read on the forums. Plug the twitch into a pc, install drivers, then unplug and back into the macbook. it worked twice, now it doesn't correct the problem anymore.
It's as if something about the driver only works once when it's installed and get's all messed up as soon as you turn the computer off or unplug the twitch and they won't work again.
I'm really kicking myself for buying a novation controller instead of a native instruments controller, if I had gone that way I would know beyond andy doubt that it would work, regardless of if it's an older model since they keep their drivers updated and working. I recognize the twitch is no longer produced so it's probably not going to be a priority at all to make sure the usb drivers actually work, but I really don't want to have thrown $300 in the garbage by buying it.
This is a very common problem, a very obvious problem that many have reported but continues to be ignored. I'm really disappointed and wish I had bought the native instruments controller instead.