Recs.
Updated
SpecsUpdate
Pros
Pro A visual scripting system for non-coders enables quick prototyping
Blueprints are authoring tools designed for non programmers so designers and other team members can help tweak and prototype. UE4's Blueprint scripts resemble flowcharts where each box represents a function or value, with connections between them representing program flow. This provides a better at-a-glance indication of game logic than a simple list of events, and makes complex behaviors easier to accomplish and games a lot faster to prototype.
Cons
Con Slow
Compared to other engines, UE4 seems to perform various actions considerably slower. Actions like starting the engine, opening the editor, opening a project, rebuilding shaders, updating references, calculating lightmaps, saving projects, etc take long enough to get irritating and end up wasting precious development time.