For me when I upgraded to 4.0 it was a big difference. After learning and understanding what the machine was throwing at me on 3.2, I was having to relearn everything over again. There were many times where I went back and forth between versions, and then just had to settle with one to prevent confusion. I would say if you master a version not to switch because it can cause lots of frustration. With 4.0 I feel that the Deus runs smoother and is not as much erratic, especially around trash/iron. Being a coin shooter, I like the way audio response sounds on 4.0, so I can pick out the deep targets.