if ther bigger you can usually float the 360 instead of cranking it out.
eh... about the same tho you do go directly to falling instead of the inital upward kick, and the take off might feel wierd the first few times.
I would think doing a 360 off of a cliff or cornice would be easier than off of a kicker, provided the cliff or cornice is high enough to allow ample time to rotate. You wouldn't have to drive forward into the jump as much as you would when taking off from a kicker, so balance would be easier to maintain.
I'd imagine there is less room for error on the landing because you are falling down much more quickly than when landing a kicker. You'll need the second or two of air to pull off the rotation, but all of that time is spent accelerating downward. If you under or over rotate, or land off axis, it could be really ugly because of the force you'll hit with.