Tracey
Good question!
There is quite a bit of interesting information on it here:
http://www.robertpeterson.org/obe-vs-lucid.html
For me, the dreams that start with feeling my body vibrate, being aware of my bedroom (I can see it exactly as it is, in the dim light), it feels like I'm awake but 'drugged' - those dreams are the beginning of an OBE. In the past I was afraid of this feeling (my fears projected out from me the feeling that I was being visited by something malevolent)...but now I'm not. Now, when I successfully leave my body, I can explore the living space I'm in (fly around) - and once I was taken to a completely different realm and I could see my silvery 'harness' (astral cord! woah). Wild. These dream experiences just feel so much different from a lucid dream.
A lucid dream, to me, feels totally real, but in a dream-like way. Like I'll wake up inside the dream and think: I know this is a dream, what shall I do now? Then I'll control it and do whatever I want..explore, discover and see things in different realms. They do feel 'real' to me, as though I'm exploring a different (thinner?) frequency of life/energy.
Somehow it feels different from what I'd call my OBE's. The OBE's always start with the feeling that my 'etheric body' is vibrating, shaking loose out of my physical body...
I'd like to have another one soon!
loveT