Pretty Real for me - I am as concious as I would be when awake and my mind seems to function in the same way. Sometimes the environments are very real - in my longest LD I was looking at the sky and touched the trunk of a tree and it was like I was really standing there, the bark was so realistic. Some
of the times the environments have been hazier and less vivid. I think that all LD's are as real as
real life but it is your recall that determines your memory of them when you wake up as even if they
are ultra real while you are in them if your recall is bad then you won't remember it well upon awakening.

The brain is what gives you your experience of the waking world and the dream world is no different
and no less real other than the brain has no external stimulus from the 5 senses while sleeping and
so it has to generate what it is perceiving from memories and imagination!