Five things about Unreal Enine 4's blueprint system that stood out were:
1. The option of creating a level-based and class blueprint, unlike Grasshopper which only has one area to work on.
2. The logic behind BP and Grasshopper is virtually the same, both use components that link together to give an end result.
3. Grasshopper tends to be more beginner friendly, as all the components are broken into tabs which then have drop down menus, making it easy to see every available component. Whilst BP has a search bar, it is still harder to know what is available to you.
4. Reusing a script with class blueprints is by far, much easier than reusing a Grasshopper script. Clicking and dragging the BP into UE4 is also faster than opening another Rhino file than re-referencing the geometry in Grasshopper.
5. Being able to visually see the script in action with BP is interesting as you can visually see an error whereas you cannot in Grasshopper.