Tor, while I can see both sides of this conflict it's your attitude that turns me off. "learn to fly on the sticks or get a better plane" That seems a little harsh. I can fly a knife edge all day long on the sticks. But I still use a mix on certain models. It makes the maneuver cleaner and more precise. Not trying to start a fight but people come hear for help not attitude.
To answer the first posters question. I have the mix on a switch. Most of the time I have it off. Certain things like a stall turn look terrible if your coupling is on. So I just turn it on for knife edge. If you are a thumb flyer put the mix on your spring loaded trainer switch. This way you can turn it on/off cleanly.

David