I've got one here, I don't know if its faulty or not but on one A1200 only left mouse button works on USB and PS2 mouse I tested but the mouse movement from the optical mouse is superb.
On my other A1200 it works great, but seems only el-cheapo mice works with it, my M$ super dooper mouse seems to be too Power Hungry.
I need to do more testing with it really, I didn't buy it I inherited it with an A1200 Tower I picked up and gutted for parts.
Someone at another forum was saying you could plug a Mouse and Joystick on Port 1 and it was Auto Switching but I have not tested this feature...
Steve.