The quality is actually NOT based on the effort. The effort does not compensate for the missing features.
CE V has:
Real Time GI
Large scale AO
SSDO
Proper sky
Time of day editor
Proper water
Volumetric fog
Volumetric lighting
Spatial clouds
Physically based Sun light
More shading models
Proper Anti-Aliasing
Proper POM
Proper foliage shader
Proper sun rays
Very valuable starter content (And this one alone is a reason for you to switch to CE since you want to make a forest).
The list goes on and on. All those features in use still happen in +60 FPS.
I am not being a UE4 hater here, but a jungle I’d create in CE in 2 hours takes me days to weeks in UE4 and still doesn’t look as good at all because of all the missing features.