I do like the looks of the Defender; if I were staying in my IT car, I'd likely be shopping for one come 2012. As it is, since I'm moving to a DSR, I'll either be seeing if I can make a Safety Solutions device work or, be forced to get a HANS.

But there's a key point. Any of these devices with lateral restraining capability - ISAAC, Defender, or some of the S2 devices - can only work on the position of the head relative to the shoulders. In order for restraint to happen, the shoulders must first be stopped. This is the same situation as a straight-ahead impact; the hips must be stopped before the shoulders can be stopped, before the head can be stopped (by a H+N device). So you need good tight belts, and that's why 6-pts or 7-pts are better than 5 - they do a better job of restraining the pelvis.

So in order to get the full benefit of a side-impact protective H+N, you must first have something that will stop the shoulders. A side net will do this, or a containment seat. But as already stated, I much prefer the cost-effectiveness (and other factors) of the nets.