I have just started using the Necksgen. I haven't used any others so I can't give a comparison, but I really like the ease of use of this one. I have a roadster and the roll cage is a little lower than I would like so I couldn't use a restraint that has the tall area behind my head. The most positive thing is I feel much more secure in the harness with the Necksgen on. I does limit you turning your head some which is to be expected. There is a video on Youtube of how to drill your helmet and good instructions come with the restraint. Made it real easy to do. I have no problems putting it on myself in the car after I have strapped in and put my helmet on. Hope this helps.
Curtis