Hi! Im an old Unity3d user that now switched almost completly over to UE4. Still im missing some parts of the old Unity engine. First of all the possibility to easily create prefabs and export these to a unityasset-file that is fast and easy to install. You can share these among collegues or on the web. Build a big library of assets that pops right in the scene that may include all kinds scripts, lights, cameras meshes and animations. Boom, done!
Next update, right?