I've used the mighty mouse before and was never terribly impressed. I just picked up an iMac and I thought I might as well give it another chance. It's just awful. Right out of the box (without changing any settings on the iMac), the cursor is slow and jumpy and doesn't go where I want it to. I've messed around with the setting for the mouse to no avail. Other mice work just fine. Is there hope or is it just a worthless mouse?