Ah, finally I can speak about some stuff :)
First, let's resolve the falloff object thing that was seen in video prior to release. It was moved there since Fracturing now supports falloff, it was simply renamed to suit the purpose. Now, many people are excited about ProRender and various other stuff, but for me personally I am very happy that finally we have first tangible results from core tech. Those would be the viewport enhancements and you got to love the eye candy. I want to mention that all the effects run totally smooth on my machine which has mid level gaming graphics card. Second, the introduction of first version of modelling kernel and my favorite of all time, complete new media session core interface. That thing brings massive performance increases when working with images and videos inside whole C4D and is completely independent from OS stuff. For example, if you load high res mp4 video on PV in R18 it will crawl, in R19 it flies. Same with other large image & video data. This is the jewel I am expecting people to "discover" once R19 is available to them.