There are a few Deus users here Willems. I used V4 for the first time yesterday. I set up all my programs the same as they were on V3.2. I was hunting in a wooded area with a lot of granite outcroppings. With out changing any settings I noticed right off that the Deus was more sensitive to the granite's magnetic field. The other thing I noticed is that it seemed to have a stronger iron rejection.
I never used the XY screen before but heard it was enhanced as part of the update. It seemed to be pretty accurate. Some deep round iron fooled the XY graph in 18 kHz, but when I switched to the adjacent program in 4 kHz, it identified it as iron with out any doubt.