UDK had this stigma for being overly difficult to pickup. Unity comes out with this stripped down, easy-to-pickup engine and it gains a reputation as being the “best engine for indies and solo devs!”. Unfortunately, this reputation still follows UE4 around. Just read the Unity forum threads about this particular subject. Many of the people making these claims have never taken a serious look into UDK or UE4 and they run back to Unity because that’s what they are comfortable with. Unity is only “easy” because it’s heavily stripped of features. It’s sort of like saying MS Paint is better than Photoshop because it is easier to pick up and draw circles with.
Being comfortable with 1 tool does not make another necessarily “Harder to use”. I was able to re-produce things in UE4 that I already made in Unity much more quickly because I had more tools available and a more consistent workflow. You learn one piece of Unreal and it really snowballs into the other sub-editors and things just make sense.
UE4 has done a great job with releasing tutorials and improving their documentation over the last 2 years, but I think what is needed, is a serious push into the indie market if Epic is to chew away at Unity’s market share. Perhaps rewarding indies in some way and pushing finished indie projects out there in front of people. “Made with Unity” does not sell the same way that “Made with Unreal” does and I think changing the opinions of the indie dev community might be a step in the right direction.