Ultimately, I would rather have it, than not have it. If you have missed your hard deck by 900 ft. and the unit fires and doesn't cut, it is only 3-4 seconds before you would have had to extract the rip cord to not pound in. Chances are in that scenario, you are unconscious or unfit to do so if you got that low, so I would rather have it and have a chance.
Now keep in mind that several people have pounded in with perfectly functioning AADs by other manufacturers. Why? There p/c is in the burble too long, instability etc... However, since it is a back up device. I would rather have something than nothing. You bust altitude in a sport where you have signed a waiver and thrown your life to the wind of your own will, then you are a statistic already. If you are lucky enough that the circumstances of your own folly in creating the situation where you are too low by lack of awareness, or maybe jumping with the wrong people (collision), or in the wrong condition (medical) your AAD works, well then it was your day to live, because with nothing you definitely auger in. The unit has saved 24 people. If the company continues to exist it will probably save more. You could argue that the RSL has killed with entanglements, but it has saved far more.
With that said, there is a greater risk that someone will die this year because their AAD was removed from their rig because of a SB and not replaced, than their will ever be because the AAD malfunctioned. Furthermore, it is possible that someone has already gone in with a properly functioning AAD. It is not a guarantee, but a chance that is saves you whether it works perfectly or not...
So, as an instructor and a rigger. I would rather that person had that chance.
If the company survives they may update their cutter with a single point wedge style cutter which would be more effective for a six flap rig, I would personally pay for the upgrade. That beats tossing a 1000.00 unit in the trash. The electronics in the unit don't seem to have had the freshman shielding problems of the other 2 mfgs. that they had to fix. So certainly, there is refined engineering in the product.
In the meantime, as a rigger on a six flap rig, I would make sure the grommets are stacked above the cutter and the tension is good on the closing loop. Further, I would take solace in the fact that my customer has something to potentially save their butt if they can't do it themselves.
my two cents...