UE4 blueprints are really easy to comprehend (after spending some years in C2 and CC). All you need to know is to learn a different workflow of the engine like GameMode, PlayerController, PlayerCharacter etc. It took me just about a week to learn how it works and to make a simple 3d adventure game system that have doors, rooms, transitions, player interactions, camera system... UE4 is stupid easy in comparison to Unity+Playmaker. To do exactly same thing in Unity with playmaker... i gave up after 2 weeks.
Like megatronx said, there's a lot of neat stuff exposed in blueprint nodes: timelines, delays, custom events, literally hundreds of different types variables (I really don't like in C2 that I can't make an array variable or simple vector2 variable to store XY - instead you need to make 2 separate number variables sic!).
And everything have build in help infos and tooltips, so there's no need to dig through the help online.
One thing that can be overwhelming is UE4 editor itselfs, there are a lot of buttons, options, parameters, options in options, parameters in parameters