Gap fill is great, but I was really happy to finally have a proper bridging speed for perimeters. That was something that had been driving me crazy!!! Just that improvement right there makes 4.0 worth it!
I also agree with this. MatterControl gives you the option to choose what settings you want specific to different materials and it really makes the system a whole lot more streamlined. Like S3D so far, but adding the option to choose yourself what features you want to be material or even layer heigh...
Yeah, that'd definiately also be useful for loading different PID values based on the printing material. But as far as I know you'll just have to save a different printer profile for each new script you want to use and name them after the material.