Had an opportunity to run with the Necksgen device this last weekend. A few anecdotal observations;
-Getting in and out of the car is no different from the HANS
-It fit just fine into a smallish OMP seat with integral head restraint "wings"
-Comfort wise over the clavicle, it was better than a HANS. The Necksgen has a bridge of material in this area that form fits much better.
-The quick release mechanism for the tether of the Necksgen is very simple and functionally vs. the HANS quick release there is simply no comparison. It wouldn't be an overstatement to just say that the Necksgen quick release works, and the HANS, well it is so poor that it basically doesn't. My particular race car has a very tight egress, which really means that an emergency exit requires releasing the tethers of whatever device so that I can squirm throught the opening. The HANS quick release product isn't easy to use and usually requires some futzing, not a good feature when you want it to work right now, picture being inverted and on fire. The Necksgen quick release mechanism is very easy to find and utilize, the exact thing I want.
-The design of the belt retention features is also superior to the HANS. Once the shoulder harness belt is in place on the Necksgen, I can't see how it would be able to slip off if there was any tension on it at all. Can't say the same for a HANS, there have been many occasions where I have found myself adjusting the placement of the shoulder harnesses onto the HANS, which isn't a great thing.
Overall, I am very pleased with the Necksgen, and would recommend this product over a HANS for anyone considering a head and neck restraint.
The one caveat is that currently GRAND-AM requires an approved head and neck restraint, and as of now only approves the HANS device. NASA and SCCA requires a head and neck restraint device that meets SFI 38.1, the Necksgen does meet this standard.