The guys make a lot of good points here..
However, I too am an experienced instructor and I have yet to teach a student to fly that did not benefit tremendously from a flight simulator before coming to me. Guys that come to me and have been working hard on a flight sim are already able to fly reasonably comfortably, so teaching them NOT to do the things on the list of potential bad habits is a piece of cake.
Give me the choice, I will take an open minded student that wants to learn who has been flying the sim ANYDAY over a totally new pilot although I love to teach both. What can be difficult is a student who has flown the sim who thinks they have it all figured out and does not want to listen. But that person isnt going to listen either way.

The biggest thing the sim cant reproduce accurately is taking off and landing. It teaches you the basic principles, but you dont get the feel of depth and the challenges that you face when handling a real model plane.

GET A SIM!! I recommend AFPD. I has taken me to new levels of skill that I never would have thought I could reach.

I do agree that popping the sticks is a horrible habit. Nothing drives me crazier than hearing the springs pop and watching the plane roughly maneuver. I must admit that I did it too when I started out.