I'm using two of these.
According to my hydroshop guy/Hydroinnovations, they discontinued the NG model due to low gas pressure in many states.
I have one model that works very well; it fires and stays lit most of the time. I've had two non-firing in the past 3-4 months.
My other model, which is more recent, required a LP to NG conversion kit done by Hydroinnovations, does not like to stay lit. I'm guessing the failure rate is approximately 33%. My solution was to put a cycle timer on my CO2 controller. It is set to refire every 5 minutes.
Drain to waste is the best way to run the HydroGEN. The increase in water usage (and cost is minimal). I saw a $10-15 a month increase in usage (6k watt, 20x20 area)
It works well... when it works.
A standard CO2 burner is a reliable, but absolutely brutal to run during summer months (depending on your location, of course)