Just a few comments-
Side impacts were a focus in a few presentations at the conference. They are often severe and there is little protection from the vehicle. Intrusion and impact with the vehicle interior is a concern.
As Heather said, rear-facing seats may well provide a bit more protection in a side impact. While side impact testing is not yet required in the USA, it is obvious that some forward-facing and booster models have an advantage over others. Deep side wings for the head, torso and hips help, as would any type of added protection from foam inserts.
While backless boosters can actually perform just slightly better than high back models in a frontal crash, some high back models may have a real advantage in side impact crashes. I think we will learn a lot more about this in the near future.
Based on the comments of one presenter, a properly installed and used carseat with a 5-point harness will really help in a side impact, front or rear facing. Any spot in back is relatively safe, so it sounds like you are in good shape since you have already seen a tech!