Hey, I’ve been making personal hobby projects in Unity (C#) since 2009 (and learning gamedev & 3D along the way), in 2014 I’ve switched to UE4 + Blueprints. After a few years in UE I must say that prototyping (and making game systems in general) in Blueprints is faster than in Unity, at least for me. Do you use Blueprints? If so, what kind of obstacles do you encounter?
For your other concerns, it’s worth noting that UE4 is still young, compared to Unity.