I too like the knob on the 200 apposed to the touch on the 400. I bought the 400 and it would just sit there in my area because of this. Simple fix was picking up a 10 turn rheostat and running the 400 through that. Solved the problem and put my power control in a better spot. Total cost was like $20 for the rheostat and plugs...and maybe 40 minutes of my time.