I had the rear facing seat once and it made the motion sickness on take off and landing almost unbearable. I definately thought I was going to vomit I was so sick to my stomach. I don't usually have that problem as long as I sit in the front of the plane. I noticed it was worse when stuck in the back on take off and landing.

The one incident was enough to make me switch from United to USAir when I started picking up more international travel. I am very curious to read about other's experiences with the backward facing seats and what they thought of them.